Teachers Manual: Grade 4 Fractions (Unit 11, 4B, pp.38-51)
Page501. Goals of unit
Studentswillbeabletousefractionstoexpressmeasurements.Inaddition,studentswillunderstandtheconceptofproperfractions,mixednumbersandimproperfractionsanddeepentheirunderstandingofthemeaningoffractions.Studentswillunderstandhowtoaddandsubtractlike‐denominatorfractions.
Interest
Studentstrytoexpressusingfractionstheamountleftoverfrommeasuringwithaunit.
ThinkingStudentsnoticethattheycanexpressthesamequantityusingvariousfractionalunits.
ExpressionStudentschangeimproperfractionsbackandforthtomixednumbersorwholenumbers.Also,theyareabletoaddandsubtractfractionswithlikedenominators.
KnowledgeStudentsunderstandtheconceptofproperfractions,mixednumbers,andimproperfractions.Also,theyknowhowtoaddandsubtractfractionsthathavelikedenominators.
2. Major points of unit 1) Area
Inthisunit,mixednumbersareintroduced,usingthemtoexpresstheamountleftoverfrommeasuringwithaunit.Improperfractionsareintroducedandunderstandingofthemeaningoffractionsisdeepenedbygraspingmixednumbersandimproperfractionsas“howmanyofaunitfraction.”Understandingmixednumbersandimproperfractionswillestablishthefoundationforfractioncalculationssuchasaddition‐subtraction,andmultiplication‐divisionoffractionswithlikedenominators.
2) Equivalent fractions
Here,studentswillunderstandfractionsasnumbersbyshowingfractionsonanumberlineandbyconsideringequivalentfractionsandtherelativesizeoffractionswithdifferentdenominators.Sofar,fractionshavebeenunderstoodbystudentsasawaytoexpressaquantityofsomething,butduringthisunit,studentswillgainamoreabstractunderstandingoffractionsandidentifythemasnumberslikewholenumbersanddecimalnumbers.
3) Addition and subtraction of fractions Inthirdgrade,studentslearnedsimpleadditionandsubtractionoffractions
thathavelikedenominators.Butthemaingoalinintroducingfractioncalculationwastohelpstudentsunderstandthecompositionofproperfractions[thatnon‐unitfractionsarecomposedofunitfractions].(Thecalculationsumswerelessthan1.)Illustrationsandnumberlineswereimportantmaterialstohelpstudentsunderstandthebasicideaoffractioncalculations. Inthisunit,studentswilldeveloptheirskillinadditionandsubtractionbasedonknowledgetheylearnedinthirdgrade.Fractioncalculationseemsdifferentfromthatofwholenumbersanddecimalnumbersbutstudentscanseethatthesamebasicprinciplesfromtheirpriorstudyofwholenumbersanddecimalsapplyiftheygrasptheideaofunitfractions.It’simportanttobuildmasteryofadditionandsubtractoflike‐denominatorfractionsontheunderstandingthatitisthesamebasicprincipleofcalculation[asforwholenumbersanddecimals].3. Teaching and evaluation plan Subunit Per Goal LearningActivities MainEvaluationPoints1.Howtoexpressinfractions(page38‐43,4periods)
123
Studentsunderstandhowtoexpressinmixednumbersanamountexceedingameasure‐mentunit.Studentsunderstandtheconceptof“properfraction”and“mixednumber.”a)Students
a)Studentsgraspthetopicofthisunitthroughtheprioractivityofexpressingthevolumeof
milkas
€
23L.
b)Studentslearnhowtoexpressinafractionanamountofjuiceexceedingameasurementunit.c)Studentsunderstandhowtowriteandread
1
€
34L.
a)Studentsexpress1
€
34
onanumberline.b)Studentslearnthedefinitionsof“properfraction”and“mixednumber.”a)Studentsthinkabout
(Interest)Studentstrytoexpressanamountthatislargerthanthemeasurementunit.(Expression)Studentstrytoexpressanamountthatislargerthanthemeasurementunitinamixednumber.(Knowledge)Studentsunderstandhowtoexpressanamountlargerthanameasurementunit.(Knowledge)Studentsunderstandtheconceptof“properfraction”and“mixednumber.”(Thinking)Studentsnotice
4
understandtheconceptof“improperfraction.”b)Studentsunderstandthefractionsthatareequivalenttowholenumbers.Studentsunderstandhowtochangemixednumbersintoimproperfractionsorimproperfractionsintomixednumbers.
howmanymthree
€
13m,
four
€
13mare.
b)Studentsunderstandthedefinitionof“improperfraction.”c)Studentscomparethedenominatorandnumeratorinfractionsthatareequivalenttowholenumbers.a)Studentsthinkabout
howtochange2
€
13into
animproperfraction.b)Studentsthinkabout
howtochange
€
73intoa
mixednumber.
thatimproperfractions,likewholenumbers,expresshowmanyofaunit.(Knowledge)Studentsunderstandtheconceptofimproperfractions.(Expression)Studentsareabletochangemixednumbersintoimproperfractions.(Knowledge)Studentsunderstandhowtochangemixednumbersintoimproperfractions.
2)Equi‐valentfractions(page44‐45,1period)3)Additionandsubtractionoffractions(page46‐
11
a)Studentsunderstandequivalentproperfractions.b)Studentsunderstandhowtocomparefractionswithlikenumerators.Studentsunderstandandcanperformadditionof
a)Studentsexpressthecoloredpartsasfractions.b)Usingnumberlines,studentsfindfractionsthatareequivalent.c)Usingnumberlines,studentscomparetherelativesizeoffractions.a)Studentsthinkofamathsentencetoexpressthecombinedareaofcardboardpieces
(Thinking)Studentsnoticethattheyshouldconsiderthesizeofthedenominatorwhentheycomparetherelativesizeoflike‐numeratorfractions.(Expression)Studentsareabletocomparetherelativesizeoflike‐numeratorfractions.(Thinking)Studentsgraspadditionoflike‐denominatorproperfractions(thatresultinimproperfractions)as“how
505periods)
234
like‐denominatorproperfractions(whentheanswerisanimproperfraction).Studentsunderstandandcanperformsubtractionofproperfractionsfrommixednumbers(Thewholenumberpartis1,theanswersareproperfractions).StudentsunderstandandcanperformadditionofmixednumberstooneanotherStudentsunderstandandcanperformsubtractionofamixednumberfromanothermixednumber.
of
€
35m²and
54m².
b)Studentsthinkabout
howtocalculate
€
35+54 .
c)Studentsreviewhowtoaddfractionswithlikedenominators.a)Studentsthinkofamathsentencetoexpresshowmanykgwillbeleftifyouuse
54kgofsugarfrom1
€
25kg
ofsugar.b)Studentsthinkabout
howtocalculate1
€
25‐54 .
c)Studentswillreviewhowtocalculatefractionsthathavethesamedenominators.a)Studentswillthinkabouthowtocalculate
2
€
35+1
€
15.
a)Studentswillthinkabouthowtocalculate
254 ‐1
€
35.
manyofaunitfraction”;theynoticetheycanthinkaboutitlikeadditionofwholenumbers.(Thinking)Studentsnoticethattheycanusepreviouslylearnedideasaboutadditionoffractionswhentheysubtractaproperfractionfromamixednumber(whosewholenumberpartis1)andgetaproperfraction.(Thinking)Studentsnoticethattheycanaddmixednumbersbasedontheirknowledgeofadditionofproperfractions.(Express)Studentsareabletosubtractmixednumbers.(Knowledge)Studentsunderstandhowtosubtractmixednumbers.
5 Studentsreviewandpracticethecontentsofthisunit.
“Practice”section.
4)Check(page511period)
Studentswillreviewthecontentsofthisunit.
“Check”and“Challenge”sections.
Page52About the curriculum Fractionsareintroducedinthirdgrade.Atthatpoint,studentsshouldunderstandhowtoexpressanamountlessthanameasurementunit.Inthisunit,studentslearnmixednumbers.Lesson 1 How to express fractions (page.38-43, 4 periods)
(The first period) Goals: Studentslearnhowtoexpressanamountgreaterthanameasurementunit. Preparation:1Lsquaregraduatedcontainer,enlargementofthepictureinthetextbook.1. Looking at the scene in the textbook on page 38, students become interested in how to express amounts of milk and juice.
(KeyQuestion)Howmanylitersistheamountofmilk?∙Studentsgraspthat1Lisdividedinto3equalpartsandthattheycanexpresstheamountwithfractions.
∙Studentsgraspthat,when1Lisdividedinto3equalparts,eachpartis
€
13L,
and2of
€
13Lmakes
€
23L.
(KeyQuestion)Howmanylitersistheamountofjuice?∙Studentsgraspthatthejuiceismorethan1Lbutlessthan2L.∙Confirmthatstudentsarethinkingabouthowtoexpressanamountgreaterthan1Lusingafraction.
Page53(Sample questions) 1. Let’s express the amounts with fractions.
1) Thecombinedquantitiesof5Land
€
14L.
2) Thecombinedquantitiesof2mand
€
35m.
3) Thecombinedquantitiesof3kgand
€
34kg.
4) Thecombinedquantitiesof
€
25kgand1kg.
2. Students read question 1 on page 38 and understand the content.
∙Teacherswriteonblackboardorpaper“?”frompage39(“Let’sinvestigatehowtoexpressnumbersthataregreaterthan1infractions!”).(KeyQuestion)“Let’sthinkabouthowtoexpressanumberthatisgreaterthan1infractions.”(Thinking)Studentsthinkabouthowtoexpressanamountthatisgreaterthanameasurementunit,bythinkingaboutdecimalnumbers.(Notebooks/Observation)(ExtraSupport)Ifnostudentmakesaconnectionbetweendecimalnumbersandfractionswhenthinkingabouthowtoexpress1Landtheremainder,teacherscanask“Howdidyouexpressitindecimalnumbers?Helpstudentstounderstandthattheamountofjuiceismorethan1L,sotheycancombine1Lwithpartleftoverfrommeasuring1L.(KeyQuestion)“Howmuchistheamountleftover[frommeasuringwithaunit]?(ExtraSupport)Ifthereareanystudentswhoarestrugglingtoexpressasafractiontheamountleftoverfrommeasuringwithaunit,teacherscanshowtheillustrationofthesquaregraduatedcontaineronpage38andask,“Howmanypiecesis1Ldividedinto?”
∙Understand3piecesof
€
14Lis
€
34Landmakesuretheamountofjuiceincludes
1Land
€
34L.
Page54About definitions
Themeaningofmathematicaltermsshouldbemadeclear.Asentenceorequationthatexplainsamathematicaltermiscalledadefinition.Thistextbookdefinesthemeaningof“properfraction”and“mixednumber”onpage40,andthendefines“improperfraction”onpage42.
3. Students learn how to express and read the combined quantity
of 1L and
€
34L.
(KeyQuestion)“Howdidyouexpressitusingdecimalnumbers?Howcanyouexpressitusingfractions?”(Interest)Studentstrytoexpressanamountgreaterthanonemeasurementunit,drawingontheirknowledgeofhowitisdonewithdecimalnumbers.(Notebooks/Observation/Comment)
4. Students work on the questions 1& 2 on page 40.
(Expression)Studentscanexpressanamountthatisgreaterthan1usingamixednumber.(Comment/Notebook)(ExtraSupport)Teachershelpstudentsclarifyeachaspectinturn,asneeded:“Whatisthemeasuredquantity?Howmanyunitsarethere?Howmuchistheamountleftoverfrommeasuringwiththeunit?∙Makesurestudentswritemeasurementunits(likeliterandmeter)totherightofthefractionalline,notnexttothedenominator.
2nd period Goals: Studentsunderstandtheconceptof“properfraction”and“mixednumber.”Preparation:Enlargementoftextbookillustration(p.40);Blackboardnumberline
1. Students understand that
€
1 34
can be expressed on a number
line and they grasp that mixed numbers are numbers.
(KeyQuestion)“Let’sshow1
€
34onanumberline.”
(Thinking)Studentsnoticethatmixednumberscanbeexpressedonnumberlineslikewholenumbers.(ExtraSupport)Helpstudentsnoticethatmixednumbersarenumbersbecausetheycanbeexpressedonthenumberlinelikewholenumbers.∙Readtheproperfractionsandmixednumbersshownbyarrowsonthenumberlinepage40.∙Categorizetheseintonumberslessthan1andnumbersgreaterthan1.
2.Students understand the definition of “proper fraction” and “mixed number.”
(Knowledge)Studentsunderstandtheconceptsofproperfractionandmixednumber.
Page55Structure of improper fractions
Itisimportanttounderstandunitfractionstounderstandthestructureof
fractions.Studentsshouldunderstand
€
23istwopiecesof
€
13astheyunderstood0.8is
eightpiecesof0.1.Throughtheseactivities,studentswillunderstand:1) “Denominators”expressaunitamount.(Itisthesameas“10’splace,100’s
place...”inwholenumbers.)2) “Numerators”expresshowmanyoftheunitareinthegivennumber,justas
eachnumeralinawholenumberrepresentshowmanyofthatplacevaluethereare.
3. Students work on question (1) page 41.
Usingthedefinitionsof“properfraction”and“mixednumber”identifythetypesoffractionsshownin(1)page41,inordertobecomeclearontheseterms.4. Students work on question (2) page 41.
(Expression)Likewholenumbers,fractionscanbecomparedinsize.
5. Work on question 3) page 41. 3rd period Goals: ∙Studentsunderstandtheconceptof“properfractions.”∙Studentsunderstandfractionsthatarethesamesizeaswholenumbers.Preparation:Enlargementoftextbookillustration(p.41);Blackboardnumberline
1. Students read question (3) page 41 and understand that they
need to think about how many
€
13m.
(KeyQuestion)Howmanyminlengtharethreeof
€
13m?Fourof
€
13m?
a)Usingthetapediagramandnumberline,havestudentsconfirmthatthree
€
13marethesameas1mandhavethemunderstandthatitcanbeexpressed
as
€
33m.
b)Inaddition,helpstudentsgraspthatfourmunitsarethesameas1
€
13m
andcanbeexpressedas
€
43m.
page56(Supplementary questions for p.42)
1) Let’schangeimproperfractionsintowholenumbers:
€
155,
€
183,
€
707,
€
1515,
€
444,
€
357,
€
426
• Let’sexpressimproperfractionswhosenumeratoris24andtheamountsarethesameas12,8,6,3,2,1.
2. Students understand the definition of improper fractions. (Thinking)Studentsnoticethatimproperfractions,likewholenumbers,expresshowmanyofsomeunitamount.(Notebook/Comment)(Knowledge)Studentsunderstandtheconceptofimproperfractions.(Observation/Comment)
3. Students work on question (1) at the bottom of page 42.
a)Makeclearthatinanimproperfractionthenumeratorisgreaterthanorequaltothedenominator.
4. Students work on question (2) page 42.
a)Studentsidentifyfractionsusingthedefinitionofimproperfraction,thusclarifyingtheconcept.
5. Students read question 4) and realize that, as in question 3,
they need to think about how many
€
14
’s are needed to make the
fraction. 6. Students consider the relationship between the numerator and denominator in fractions that are equal to the whole numbers 1, 2 and 3.
a)Studentsnoticethatwholenumberscanbeexpressedwithimproperfractions.
7. Students work on question (1), bottom of page 42. (ExtraSupport)Havestudentsnoticethenumeratorishowmanytimesthedenominator(howmanymultiplesofthedenominator)..
Page57About converting mixed numbers and improper fractions
Convertingmixednumberstoandfromimproperfractionsisfundamentaltoaddition‐subtractionandmultiplication‐divisionoffractions.Themostcommonmistakeinadditionandsubtractionoffractions(ournexttopicofstudy)ismistakes
inconversionbetweenmixednumbersandimproperfractions,sostudentsshouldthoroughlyunderstandconversion.Ifyoufocusonpracticingthisoperationwithoutdeepunderstanding,studentsaremorelikelytomakeerrorsontheoperation.Therefore,itisveryusefultomakeuseofnumberlinesandpicturesoffractions.4th period Goals:Studentsunderstandhowtochangemixednumbersintoimproperfractionsorimproperfractionsintomixednumbers.Preparation:Enlargementoftextbookillustration;Blackboardnumberline1. Students read question 5 page 43 and consider how to change
€
2 13 to an improper fraction. (Work Independently)
(Interest)Studentsareinterestedintherelationshipbetweenmixednumbersandimproperfractionsandinchangingonetoanother.
(KeyQuestion)“Howmany
€
13sdoyouneedtomake2
€
13?”
∙Studentsconsiderhowtochangethemixednumber2
€
13toanimproper
fraction.
1)2
€
13→2+
€
13
2)2includes6piecesof
€
13(3×2=6).Inaddition,thereis1pieceof
€
13.
Sothetotalis
!
7
3.(3×2+1=7)
3)2
€
13includes7piecesof
€
13.Sothetotalis
!
7
3.
2. Summarize how to find numerators of improper fractions when changing mixed numbers to improper fractions. 3. Students work on question 1) page 43.
(Expression)Studentscanchangemixednumberstoimproperfractions.
(ExtraSupport)Studentssometimeshavetheideathat
€
113is
€
113.
Soteacherstobesurethatstudentsunderstandhowtofindthenumeratoroftheimproperfraction.
4. Students think about how to change
!
7
3 into a mixed number.
(KeyQuestion)“Howmany
€
33sarein
!
7
3?”
(ExtraSupport)Referringtothenumberline,studentsthinkabouthow
many
€
33sarein
!
7
3.
5.Summarize how to find the whole number and numerator when converting an improper fraction to a mixed numbers. 6. Students work on question 1) page 43.
(Expression)Studentscanchangeimproperfractionsintomixednumbers.Page581st period About the size of fractions
Intheteachingofequivalentfractions,itiscentraltohelpstudentsunderstandthatmanydifferentfractionalunitscanbeusedtoexpressthesameamount.Sowhenconsideringfractionswithdifferentdenominatorsonthenumberlineandwhenconsideringtheirrelationship,itisimportanttomaketheconnectionbetweenthenumberlineandthesquareareaillustrationsothatstudentscanseetheamount.Inshort,teachersshouldteachequivalentfractionsusingboth1)and2)onpage44.Throughthislesson,studentswillunderstandequivalentfractionssuch
as
€
26=
€
13,
€
68=
€
34,
€
410=
€
25.
Goals: ∙Studentsunderstandequivalentproperfractions.∙Studentsunderstandhowtocomparefractionsthathavelikenumerators.Preparation:Enlargementoftextbookillustration;Blackboardnumberline
1. Students express the colored parts as fractions and find that there are many fractions that are equivalent.
(KeyQuestion)“Let’sexpressthecoloredpartsasfractions.”a)Studentsrealizethatallofthecoloredpartsarethesamesizefromthe
illustrationsinthetextbookandtheyunderstandthat21 canbeexpressed
withmanydifferentfractions(21 =
€
24=
€
510).
2. Students read question 2 page 44 and find fractions that are equivalent. (Work Independently)
(KeyQuestion)“Let’sfindfractionsthatareequivalentusingthenumberlinesbelow!”
a)Havestudentsrecognizethat21 =
€
24=
€
510andthatinaddition,thereare
otherfractionsthatareequivalent.
3. Students work on ★1 on page 45 and use the number line to
see that there are also equivalent fractions for
€
13 and for
€
23.
(Expression)Studentscanfindequivalentfractions.(ExtraSupport)Forstudentswhoarestrugglingwithfindingequivalentfractions,teacherscanadvisestudentstochecktheillustrationsonpage44.Studentswillunderstandwhatisequivalentbynotingwherethemarksonthenumberlineare.∙Afterstudentsfindequivalentfractions,teachershavestudentsexpress
theminequationssuchas
€
13=
!
26=
€
39,
€
23=
€
46=
€
69andhelpstudentsnoticethat
thesamevaluecanbeexpressedwithvariousfractions.Page594. Students read the question 3 page 45 and investigate the
relative sizes of fractions that have the same numerator.
(KeyQuestion)“Whichisbigger,21 or
€
14?Explainwhy.”
(Thinking)Studentsnoticethattheyshouldconsiderthesizeofdenominatorwhentheycomparetherelativeamountsoffractionsthathavelikenumerators.(ExtraSupport)Teacherhelpsstudentsunderstandthatthegreaterthedenominator,thesmallerthesizeofthefraction.
(KeyQuestion)“Whichisbigger,
€
23or
!
26?Andwhy?”
Buildingonwhattheylearnedaboutfractionswithanumeratorofone,studentswillunderstandthatforfractionswithanumeratoroftwo,also,thegreaterthedenominatorvalue,thesmallerthesizeofthefraction.(ExtraSupport)Forthestudentswhocannotfindtheanswer,teacherscaninstructthemtoreview★1and★2,thenadvisethem,“Howdidyoucomparefractionswhentheirnumeratorswere1?”
5. Summarize that for fractions that have the same numerator, the greater the value of the denominator, the smaller the size of the fraction. 6. Students work on (1) at the bottom of page 45. 7. Students review this sub-unit and write in their journals.
Page60Addition and Subtraction of fractions
Theaimofthisunitisforstudentstounderstandhowtoaddorsubtractfractions.Regardinginstructionforproblem1atthetopofpage46,teachershelp
studentsunderstandthat
€
35includesthree
€
15s,54 includesfour
€
15s.Sincetogether
thereareseven
€
15s(3+4=7)theproblemcanbesolvedas
€
35+54 =
€
75.Inthesame
way,question2onpage47,canbesolvedbythinkingaboutthenumberofunit
fractions“7‐4=3So
€
75‐54 =
€
35.”
Attheend,drawconclusionsaboutcalculationmethods.Themostimportant
pointofinstructionhereistohavestudentsnoticetheunitfraction
€
15andto
discoverthatiftheyuseittheycancalculatefractionsinthesamewayaswholenumbers(3+4=7).Whenthistopicisfirstintroduced,thereareseveralcommon
mistakessuchas
€
35+54 =
€
710,
€
75‐54 =
€
30,
€
75‐54 =3.Soteachersshouldtrytodeepen
understandingofthecompositionoffractionsas“howmanyofaunitfraction.”
3. Addition and subtraction of fractions (pages 46-50. 5 periods) 1st period Goals: Studentswillunderstandandperformadditionofproperfractionswiththesamedenominator(whentheanswerisanimproperfraction).Preparation:Enlargementoftextbookillustration1. Students discuss the scene in the textbook and become interested in the question. 2. Students read question 1 on page 46 and understand the contents.
(KeyQuestion)“Whatdoyouknowinthisquestion?Whatareyoutryingtofindout?”
3. Students think about how many m of cardboard they used altogether.(Self-solving)
(KeyQuestion)“Whatkindofmathsentencedoyouneedtofindtheanswer?”
(ExtraSupport)Forthestudentswhoarestrugglingwithmakingamathsentenceforthisquestion,Teacherscanasksomethinglike,“ifyouchange
€
35mto3m,
54mto4m,whatkindofmathsentencecanyoumake?”
4. Students grasp the goal of this unit (to understand how to add
proper fractions) by thinking about how to calculate
€
35
+45. (Work
Independently)
(Keyquestion)“Howdoyoucalculate
€
35
+45?”
(Interest)Studentsnoticethattheycancalculateitinthesamewayaspreviousadditioncalculationsiftheymakeuseoftheconceptofunitfractions.(Notebooks/Comments)(ExtraSupport)Referringto★2teachershelpstudentsunderstandthattheyneedtoknowhowmanyoftheunitfractionstherearealtogether.
5. Students present and discuss their calculation methods. a)Studentsrealizethattheycancalculateeasilyiftheymakeuseofthe
knowledgeof
€
15(unitfraction).
6. Summarize how to add fractions that have the same denominator. 7. Students work on question (1), bottom of page 46. Page61How to express the answer of calculation
1) Atelementaryschool,whenstudentsarestillgraspingthesizeoffractions,
whentheanswertoacalculationisanimproperfractionsuchas
€
107,asa
generalrulewehavestudentschangetheimproperfractiontoamixed
number(1
€
37)becauseitiseasierforstudentstounderstandthesizeasa
mixednumber.(However,leavingtheansweras
€
107ismathematically
correct.Soteacherscanacceptitasacorrectanswer,dependingontheiragreementwiththestudents.)Butinwordproblems,teachersshouldguidestudentstochangeimproperfractionstomixednumbersinordertounderstandthesizeoffractions.
2) Iftheansweris3and
€
75,studentsneedtochangeitto4
€
25because3
€
75is
neitheramixednumbernoranimproperfraction.(Teachershavetohelpstudentsdistinguishthisfromthewholeexpressedasanimproperfraction,asin(1).)
3) Note,ifanswersbecome
!
26or
€
36,studentsdonothavetosimplifythemto
€
13
or21 becausetheystudysimplificationinfifthgrade.
2nd period Goals:Studentsunderstandandcanperformsubtractionofproperfractionsfrommixednumbers(Thewholenumberpartis1,theanswerisaproperfraction).Preparation:Enlargementoftextbookillustration.1.Students read question 2 page 47, understand the content and write a math sentence.
(Keyquestion)“Let’swriteamathsentenceforhowmanykgwillbeleft.”
2. Students think about how to calculate 1
€
25‐54
.
(Keyquestion)“Let’sthinkabouthowtocalculate1
€
25‐54 .Canyoucalculateit
inthesamewayasaddition?”(Thinking)Studentswillnoticethatwhensubtractingfractionsthathavethesamedenominators,theycandrawontheirpriorlearningaboutadditionoffractions,andusethesamekindofthinking.(Notebooks/comment)(ExtraSupport)Teachershelpstudentsrecallthatinadditiontheyconsideredhowmanyunitfractionsthereare.
3. Students will present how to calculate 1
€
25‐54
.
a)Teachersshouldmakestudentschange1
€
25to
€
75inordertocalculate1
€
25‐
54 inthesamewayasaddition.Usingtheideaofunitfraction,theanswerof
1
€
25(
€
75)‐ 54 canbeelicitedbyjustsubtractingnumerators.(7‐4)
4. Summarize how to subtract fractions that have the same denominator.
5. Students work on question 1) page 47. Page62Calculate whole parts and fractional parts separately
Whenweaddwholenumbers,weaddthetensplacetothetensplaceandtheonesplacetotheonesplace.Thismeansthatnumbersthatrepresentthesameunitscanbeaddedtoeachother.Itisimportanttohelpstudentsunderstandhowtoaddmixednumberstomixednumbersusingillustrationsorsomethingsimilar.Thenstudentsshouldcomparetheoperationlearnedinthislessonwithwholenumberadditionsothattheynoticethatmixednumbersandwholenumbershavethesameprinciplesofaddition.3rd period Goals:Studentsunderstandhowtoaddmixednumberstooneanotheranddemonstrateit.Preparation:Enlargementoftextbookillustration.1. Students read problem 3 page 48 and understand the context of this lesson. Then they will think about how to calculate
2
€
35+1
€
15. (Work Independently)
(KeyQuestion)“Let’sthinkabouthowtocalculate2
€
35+1
€
15.”
(Interest)Studentswilltrytorelatemixednumberadditiontothatofproperfractions(Notebooks/Comments)(ExtraSupport)Teachershelpstudentsattendto★1andexplainthesimilaritybetweencalculatingwithmixednumbersandproperfractions.
2. Students present and discuss their calculation methods.
(Thinking)Studentsnoticethattheycanaddmixednumbersbasedontheirknowledgeofadditionofproperfractions.
3. Summarize addition of mixed numbers. ∙Makesurestudentsknowhowtoaddmixednumbers.Onemethodistoseparatemixednumbersintowholenumberpartsandfractionalparts.Theothermethodistochangemixednumberstoimproperfractions.
4. Students will work on 1), 2) page 48. a)Forproblem1(3)nearthebottomofp.48,Havestudentsconsiderwhosemethodisbetter,Makoto’sorNaoko’s?b)Fortheproblemsin2atthebottomofp.48,thefractionalpartsbecomeimproperfractions,sostudentsneedtonoticethattheymustbeconvertedtowholenumbers.Problemsconvertingtomixednumberswillberevealedbytheseproblems,sotherelationshipbetweenmixednumbersandimproperfractionscanbetaughtagaincarefullyforstudentswhomakemistakes.
Page63Supplementary question
4) Therewasa6
€
38mtape.Youusedsomemetersso3
€
78mwasleft.Howmany
metersdidyouuse?4th period Goals: Studentsunderstandhowtosubtractmixednumbersfromoneanotheranddemonstratethosecalculations. Preparation:Enlargementoftextbookillustration.1. Students read question 4 page 49 and think about how to
calculate 254 ‐1
€
35.
(KeyQuestion)“Whatisthedifferencebetween254 ‐1
€
35andprevious
subtractions?”(Possiblereactions)a.Bothofthenumbersintheproblemaremixednumbers.
(KeyQuestion)“Canyoucalculate254 ‐1
€
35usingthemethodsusedfor
additionwithmixednumbers?”(Interest)Studentstrytoperformmixednumbersubtraction,referringbacktoadditionwithmixednumbersorsubtractionwithimproperfractions.(Notebooks/Comments)(ExtraSupport)Teachershelpstudentsattendto★1andaskhowthecalculationmethodsofthetwostudentsdrawonpreviouslearningaboutfractioncalculation.
2. Summarize how to calculate. ∙Summarizesubtractionmethods.Onemethodistoseparatemixednumbersintothewholenumberpartsandthefractionalparts.Theotheristochangemixednumberstoimpropernumbers.
3.Students work on problem (1) at the bottom of page 49. Teachershavestudentsthinkaboutwhichcalculationmethodisbetterfor
parts(2)and(3)ofproblem1.4. Students work on (2)
Sincethefractionalpartcan’tbesubtracted,havestudentsgraspthattheminuendneedstobeconverted.
Page64Relationships between whole numbers, decimal numbers and fractions
Somestudentsgraspwholenumbers,decimalnumbers,andfractionsasverydifferentthings.Thisisespeciallytrueoffractionsbecausetheydonotfollowthebase‐10structureofwholenumbersanddecimalnumbers.
Thoughadditionandsubtractionoffractionsthathavethesamedenominatorsisthefocusinthisunit,studentsareexpectedtoestablishthefoundationtounderstandwholenumbers,decimalnumbersandfractionsasnumbersbecauseallofthemarecalculatedbasedonunitamounts.5th period Goals: Studentswillapplyandpracticethecontentsofthisunitincluding:
1) Problemsthatbuildunderstandingofthemeaningofproperfractions,mixednumbersandimproperfractions.
2) Problemsthatbuildunderstandingoftherelationshipbetweenproperfractions,mixednumbersandimproperfractions.
3) Problemsonadditionandsubtractionoffractionsthathavethesamedenominators.
Math Story Goal:Withunderstandingofthecompositionofwholenumbers,decimalnumbers,andfractions,studentswillcomprehendthatadditionandsubtractionproblemswiththesamedenominatorscanbecalculatedinthesamewayaswholenumbersanddecimalnumbers.page653.Check (page 51,1 period) (Goals of 1st period)
Checkhowmuchstudentsunderstandthisunit.1.Problemsthatassessunderstandingofthemeaningof“properfraction”,“mixednumber,”and“improperfraction”andoftheconversionbetweenmixednumbersandimproperfractions.2.Problemsthatassessunderstandingofrelativesizeoffractions.3.Problemsthatassessadditionandsubtractionthatoflikedenominatorfractions.
Challenge (page 51 no period) Goals: Bymakingmagicsquares,studentsdemonstrateandpracticeadditionandsubtractionoffractionsthathavethesamedenominators.
“Magic Squares”
Here,studentsextendtheirpreviouslearninginordertocalculatefractionadditionandsubtractionproblemswith3terms.Forthesecalculations,
1) Calculatethefirst2terms,thenoperateonthethirdtermandtheanswerfromthefirstcalculation.Intheprocessofthoseoperations,evenifthe
answersbecomeimproperfractionssuchas
€
117,wegoonthenextoperation
withoutchangingittomixednumbers.2) Ifyouneedtodoonlyaddition,youcanadd3termsatonceasyoudowhen
youadd2terms.Inthatcase,youhavetomakesuretochangeimproperfractionstomixednumbersattheendofthecalculation.Whenyouarecalculatinginthisway,youshouldseparatefractionsintothewholenumberpartandthefractionalpartandthencalculate.Ifthefractionalpartsofthoseanswersbecomeimproperfractionstheyshouldbechangedtomixednumbersaslearnedinthisunit.
Teachersshouldfocushereonpracticeadditionandsubtractionof3terms.Butcalculationsmoredifficultandcomplexthan3termsneednotbeintroducedtostudents.
Research Volume of Teachers’ Manual1. Goals of this unit (see 4B teachers’ manual unit goals, p. 1)
Studentswillbeabletousefractionstoexpressmeasurements.Inaddition,studentswillunderstandtheconceptofproperfractions,mixednumbersandimproperfractionsanddeepentheirunderstandingofthemeaningoffractions.Studentswillunderstandhowtoaddandsubtractlike‐denominatorfractions.
(Seeadditionalgoalsrelatedtoassessmentpointsshownonthefirstpageoftheaccompanying4Bteachers’manualvolume.)2. The structure and development of the curriculum over grades 3-6 3rd grade (unit 16)
1) Meaningofdividinganamount.2) Expressmeasurementamountwithfractions.(properfractions)3) Expressfractionsonanumberlineandunderstandtherelativesizeof
fractionswithlikedenominators.(properfractions)4) Addandsubtractfractionswithlikedenominators.
4th grade (this unit) 1) Theconceptofproperfractions,mixednumbers,andimproperfractions.2) Expressfractionsonnumberlinesandunderstandrelativesizeand
equivalentfractions.3) Convertimproperfractions,wholenumbers,andmixednumbers.4) Addandsubtractfractionswithlikedenominators.(properfractionsand
mixednumbers)5th grade (unit 10)
1) Relativesizeandequivalenceforfractionsthathavedifferentdenominators.2) Characteristicsoffractions,fractionreduction,leastcommondenominator.3) Addandsubtractfractionswithunlikedenominators.
The 5th grade (unit 11) 1) Meaningoffractions(quotientofdivisionmeaning)2) Relationshipbetweenfractions,decimalnumbersandwholenumbers,and
howtoconvertbetweenthem.
3. Interpretation of Teaching Materials Inthirdgrade,studentshavelearnedthattoexpressanamountlessthana
measurementunit,theycandividethemeasurementunitintosomenumberofequalpartsanduseaproperfractiontoexpressit.
Inaddition,studentshavelearnedthatfractionscanbeexpressedonanumberline.Usinganumberline,studentsgraspedthestructureoffractionsusingtheideaofunitfractionsandpracticedsimpleadditionandsubtractionoffractionswithlikedenominators.
Inthirdgrade,studentslearnedabouttheadditionandsubtractionofsimplefractionswithlikedenominators,buttheemphasiswasondeepeningunderstandingofthestructureofproperfractionsandunderstandingthattheycanbeaddedandsubtractedlikewholenumbers.Therefore,inthirdgrade,theystudiedfractioncalculationsforamountslessthan1usingpicturesandnumberlines.
Inthisunit,mixednumbersareintroduced,andinadditiontousingthemtoexpressameasurementamount,studentswillplacethemonanumberlineandcomparethesizeoffractionswithdifferentdenominators.Fractionsthathadbeenconsideredasmeasurementamountsandmissingpartsuntilnowwillbemademoreabstract,sothattheycanbeseenasnumbers,likedecimalsandintegers.
Inaddition,studentswilllearnimproperfractionsandhowtoconvertbetweenimproperfractionsandmixednumbers.Thisprovidesafoundationforadditionandsubtractionoffractionsthathavethesamedenominatorsandunderstandingmultiplicationanddivisionoffractionsthatcomeslateringrade6.
Throughthisunit,studentswillbecomemorefamiliarwithvariousfractioncalculations.Additionandsubtractionoffractionsseemdifferentfromthatofwholeanddecimalnumbersbutinfactbothofthemrelyontheideaofadditionofunits.Therefore,itisimportanttounderstandtheconceptofunitfractions.
Whenacalculationresultsinanimproperfraction,itismathematicallycorrecttoleaveitinthatform.However,becauseitiseasierforstudentstounderstandthesizeoffractionswhentheyareshownasmixednumbers,weencourageteacherstohavestudentsroutinelyconvertanswersintomixednumbersfromimproperfractions.Thistextbookusesfractionswithdenominatorsthatarelessthan10becausewewantstudentstounderstandadditionandsubtractioncalculationmethodsandtoconnectwhattheylearninthisunittodailylife.3. Instruction of this unit How to Express Quantities as Fractions Sub unit 1 (page 38-43)
Tohelpstudentsunderstandtheconceptofproperfractions,mixednumbersandimproperfraction,thisunitfollowsthesesteps:
1) Throughmeasuringanamountofjuice,studentslearntouseamixednumbertoexpressanamountthatincludesafractionalpartofameasurementunit.
2) Afterlearningthatmixednumbersexpressanamount,studentsgobeyondthattolearnthatmixednumbersarealsonumbers,becausetheylearnthatunitfractionscanbeexpressedonanumberline.
3) Basedontheknowledgeof2),studentslearnthedefinitionofproperfractionsandmixednumbers.
4) Usingthenumberlineasanaid,studentsunderstandthestructureoffractionsbyaccumulating2,3,4…ofaunitfraction,andinthiswaystudentsunderstandfractionslargerthan1asaccumulationsofunitfractions,andusethistounderstandthedefinitionofimproperfractions.
5) Studentswillexpressimproperfractionsonanumberlineandtrytofindfractionsthatarethesamevalueofwholenumbers.Thisknowledgehelpsstudentsconvertbetweenimproperfractionsandwholenumbers.
6) Basedon5),studentswillunderstandhowtoconvertbetweenmixednumbersandimproperfractions.
Equivalent Fractions, the second sub unit (page 44-45)
Studentswillconsiderequivalentfractionsandrelativesizeoffractionsbyshowinghowfractionswithvariousdenominatorscanbeexpressedonanumberlinebyfindingthesameunitamount.
1) Studentswillinvestigateequivalentfractionsthathavedifferentdenominators.
2) Studentswillinvestigaterelativesizeoffractionsthathavedifferentdenominators.
Throughthoseactivities,studentswillunderstandthatfractionsexpressnumbers,whichcanbecomparedbyrelativesize,justaswholenumbersanddecimalnumbersexpressnumbers.Addition and Subtraction of Fractions, the third sub unit (page 46-50) Additionandsubtractionoffractionswiththesamedenominatorscanbedonejustaswithwholenumbers.Studentswilllearnaboutthiswiththestepsbelow.
1.Additionofproperfractions(includescarrying)2.Subtractionofproperfractionfrommixednumber(wholenumberportionofmixednumberis1;includesregrouping);subtractionofproperfractionsfromeachother.3.Additionofmixednumbers(withandwithoutcarrying)4.Subtractionofmixednumbers(withandwithoutregrouping).
6. Explanation of Unit 11 and Notes for Instruction Meaning of fractions
Fractionsareintroducedinthirdgradetoexpressanamountthatislessthanameasurementunit.Hereinfourthgrade,studentswilllearnhowtoexpressanamountlargerthanameasurementunitinfractionsandwilllearnproperfractions,mixednumbers,andimproperfractions.
Sofar,fractionshavebeentaughtasthewayofexpressingsizesofanamount.Here,fractionsareintroducedasthewayofexpressingthesizesofdiscreteandcontinuousquantitiesaswholenumbersanddecimalnumbers.
Wholenumbersareusedtoexpressnotonlythesizeofanamountsuchas“3people,”“3papers”and“3cm”butalsotherelationshipbetween2amountssuchas“3times.”Likewise,fractionshaveseveralmeanings,listedbelow.Note,thesemeaningsarenoteasilyseparatedbutratherareverycloselyrelated.Wecategorizethemheretohelpwithorderingtheideasforinstruction.
1) Fractions which express the size of amounts (grade 3,4) Ifyouwanttoexpresshowmanypapersyouhave,howmanypeopleare
here(discretequantities)youcanusewholenumberstoexpressthem.But,ifyou
wanttoexpresssomeamountofwater(
€
2 34L)orlength(
€
23m),whicharecalled
continuousquantities,youhavetochooseaunitamounttomeasurethem.Theremaybesomeamountleftoverfrommeasuringwiththatunit.Decimalnumbersandfractionswereoriginallycreatedtoexpressthesecontinuousquantities.
2) Fractions as quotient of division (grade 5 /unit 11)
€
23expressesthequotientof2÷3.Thisconceptwillbeintroducedinunit11in
gradefive.BetweenwholenumbersAandB,theanswersofA+B,A‐B(A>B),A×Barealwayswholenumbers.ButtheanswerforthemathsentenceA÷B,isnotgenerallyawholenumber;itprobablyhasaremainder.But,ifyouexpresstheanswerwithafraction,A÷Bisalwayspossible.Thisisanimportantfunctionoffractionsasnumbers.
3) To express ratio (grade 5)
Themeaningof
€
23inthiscaseistherelativevalueof2and3:when3is
regardedas1,then2canberegardedas
€
23.Thisinterpretationoffractionsis
introducedfollowingthetreatmentoffractionasquotientinGrade5,unit11,“FractionsandDecimalNumbers.”Fractionsasratioscanbethoughtofinthesamewayas“3timesasmuch”forintegers.4) Part-Whole Fraction (grade 3)
“
€
23of12”or“
€
23of3m”arecalled“part‐wholefractions.”(grade3)Part‐whole
fractionsexpresstwopartsofanamountthatisdividedinto3equalparts.Herefractionsareviewedasoperationsanddonotexpressnumbers.
Ifstudentsstudypart‐wholefractionstoomuch,theywillunderstand
€
23as
“÷3×2”anditwillconfusestudents’understandingoffractionsasnumbers.Therefore,4)isexplainedonlyinthecontextofteachersintroducinghowtoexpressthefractionalamountleftoverfrommeasuringwithaunit.To understand fractions as numbers
Evenifstudentsexpressthelengthofatapeas
€
35m,wecannotbecertainthat
theyunderstandfractionsasnumbers.Somestudentsmaybethinkingaboutthe
conceptofmeasurementfraction(
€
35mis3piecesof1mdividedinto5equalparts)
anddonotunderstandfractionsasnumbers.Therefore,teachershavetomakesurestudentsunderstandfractionsasnumbers.
Studentslearnedtothinkaboutwholenumbersbyreplacingconcretematerialssuchasapplesorpaperswithabstractmaterials(picturesofsquaresandtapediagrams),thencomparingthemonthenumberline.
Thesameapproachcanalsobeusedtohelpstudentsunderstandfractionsasnumbers.Thistextbookunitfirstintroducesfractionsusinganamountofwater,thenreplacesthiswithapictureofasquare,andfinallymovestoexpressingtheamountonanumberline.
Onanumberline,allnumbers(0,1,2….)areplacedatequalintervals,andcontinuousquantities,discretequantities,andunitsareallrepresentedbynumbers.Byplacingfractionsonanumberline,studentsclarifythatfractionsarenumbersandareabletoprogressbeyondthinkingoffractionsaspiecesofawhole.
Studentsdeepentheirunderstandingoffractionsasnumbersthroughrepresentingthemonthenumberline,comparingtheirrelativesizes,andaddingandsubtracting.
Instruction on addition and subtraction of fractions
Tounderstandadditionandsubtractionoffractions,firstofall,studentsshouldunderstandthatfractionsaremadeupofunitfractions.Inaddition,theyhavetounderstandequivalentimproperfractionsandmixednumbersandhowtoconvertbetweenthem.Therefore,teachersshouldhavestudentspracticethesecalculationsafterteachingtheseideas.
Foundation of addition and subtraction of fractions
Whenstudentsarecalculatingfractions,someofthemarelikelytomake
mistakessuchas“
€
35
+15
=410.”Studentsseethedenominatorsandwanttoaddthem,
justastheyaddthenumberineachplacevalueinthecaseofadditionofintegers.Forthisreason,itisbestforteacherstoprovideacontextofmeasurement
(e.g.,length)whenintroducingadditionoffractions,andaconcreteexamplesuchas
“howmanymetersare
€
35mand
€
15mintotal?”Itisimportantforinstructiontofocus
ontheideathat“
€
35is3piecesof
€
15and
€
15is1pieceof
€
15.Sotogetherthereare
3+1=4piecesof
€
15andtheansweris
€
45,ifyouregard
€
15astheunitamount.”Unit
fractionshelpstudentsunderstandthatfractionalcalculationsaredoneinthesamewayasforwholenumbers.
2) Calculation with mixed numbers that require carrying or regrouping
Whenyouaddorsubtractmixednumbers,youaddorsubtractwholenumberpartsandfractionalpartsseparately.Thisideaisveryusefulbecauseitlikecalculatingwithwholenumberswithtwoplaces.Therefore,whenteachersare
teachingadditionandsubtractionofmixednumbers,itiseffectiveforthemtohavestudentsrecallhowtheylearnedaboutadditionandsubtractionoftwo‐digitwholenumbers.
However,manystudentsmakemistakeswhencarryingorregroupinginadditionandsubtractionofmixednumbers.Thesemistakesseemtooccurbecausefractionalcalculationscannotbeperformedasautomaticallyaswholenumbersordecimalnumbers,whichbothusethebasetensystem.Therefore,studentsshouldexplaintheirthinking,ratherthanjustcalculatequickly,whenpracticingcalculations.Page481.Goal
Studentsunderstandhowtoexpressanamountlargerthanameasurementunitwithmixednumbers.
2. Assessment Criteria
(Interest)Studentsexpressanamountlargerthanameasurementunitwithfractions.(Thinking)Studentscanthinkabouthowtoexpressinfractionsanamountlargerthanameasurementunit,byconsideringhowthisisdoneindecimalnumbers.(Expression)Studentsexpressanamountlargerthanameasurementunitwithmixednumbers.(Knowledge)Studentsunderstandhowtoexpressanamountlargerthanameasurementunitwithmixednumbers.
3. Teaching Point Relation of mixed numbers
Inthisunit,studentsshouldunderstandhowtoexpressanamountlargerthanameasurementunitusingknowledgeofproperfractionsfromgrade3,wheretheyexpressedanamountsmallerthanameasurementunitbyrelatingtodecimalnumbers.
4. Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize*; Assessment & Extra Support +
1.Students look at the scene on page 38 and think about how many L of juice there are. Students get interested in the illustration.
Students understand the situation in the textbook: To measure milk, it has been put in a graduated 1L container divided into 3 equal parts, and the quantity
*Teachers show a carton of milk and students get interested in the textbook illustration. *Fractions are introduced in
(K) ”What is happening in the illustration in the textbook?” (K) “How many L of milk are there?”
of milk is 2 parts (Possible reactions) 1) Students try to measure how many L by pouring milk into the 1L square graduated containers.
2) There are 2 parts of
€
13
L.
So the quantity is
€
23
L.
grade 3. The purpose of introduction here is to remind students that fractions express how many unit fractions of an amount divided into some number of equal parts.
2. Students will look at the scene on page 38 and discuss the quantity of juice. They understand the lesson’s purpose. (K) ”How many L is the amount of juice?” (K) “Today, let’s think together about how to express fractions that are greater than 1. ”
Students think about how to express the amount of juice in liters. (Possible reactions) 1) Juice is more than 1L but less than 2L. 2) It is about 1.8L 3) It is 1L plus and amount less than 1L. Students write the goal of this lesson in their notebooks: “Let’s think about how to express fractions that are greater than 1.”
*Teachers show the illustration in the textbook and students discuss the quantity of juice. Students grasp that there is more than 1L of juice. *Students grasp the lesson’s purpose.
3.Students read the question and understand the meaning of it. They express the part less than 1L as a fraction (independent work). (K) “First of all, let’s express as a fraction the amount that is leftover from measuring 1L.
Based on the previous lesson, students express the left over part as a fraction by themselves. (Possible reactions) Students express the left over part as a fraction.
1)
€
34
L
2) 1L that has been divided into 4 equal parts and there
are 3 of them. So it is
€
34
L.
3 )We learned it in grade 3.
It is
€
34
L.
* Teacher draws a square graduated container for juice like that in the textbook, on drawing paper posted on the blackboard, or on projector. * Textbooks are closed. + For students who are struggling to express the left over part as a fraction, teachers can use a copy of the illustration on the textbook and ask them questions like “how many equal parts is 1L divided
into.”
4.Students learn how to express and read the total of
1L and
€
34
L.
(K) “With decimal numbers, you can express 1.3 by combining 1 and 0.3. Likewise, you can express
the amount here as
€
1 34
by
combining 1L and
€
34
L. ”
Students discuss how to express the total of 1L and
€
34
L.
(Possible reactions) 1) With decimal numbers, we expressed the combined amount of 1L and 0.3L as
1.3L. So this is
€
1 34
L.
Students learn how to express mixed numbers and write the amount of juice in mixed numbers in their notebooks.
(Interest) Students relate fractions to decimal numbers, and try to express an amount that is greater than 1 unit in fractions. Students confirm from the picture that the volume of juice is one liter plus 3 of 4 equal parts of one liter.
5, Summary of how to express a fraction greater than 1 and practice.
Students understand how to express as a fraction an amount that is greater than 1. Students see that it is not just for liters, and they confirm how to express, for example, length (2m and
€
34
m) and weight (3kg and
€
15
kg) in mixed numbers.
(Possible reactions)
1) It is
€
2 34
m.
2) It is
€
315
kg.
Summary that, as for decimals, an amount that is greater than 1 can be expressed by combining the whole number part and the fractional part. Students do practice questions 1) and 2) page 40. Students discuss the
(Knowledge) Understand how to express an amount that is greater than 1 measurement unit in a mixed number. Teachers confirm that students can express an amount greater than 1 measurement unit as a fraction, and introduce definition. (Thinking) Students make a connection to decimal numbers to express an amount larger than a measurement unit. (Expression) Students express an amount larger than a measurement unit using mixed numbers.
benefits of being able to express an amount that is greater than 1 as a fraction.
5. Example of black board organization Howmanylitersofjuicearethere?Goal ‐Let’sthinkabouthowtoexpressfractionsgreaterthan1.What is the volume left over after measuring one liter?
‐Itis3outof4equalpiecesof1L.So,itis
€
34L.
How can we express 1L and
€
34L?
‐Indecimalnumbers,itwasexpressedas1.3Lbycombining1Land0.3L.Summary
‐Wecombine1Land
€
34Landexpressitas
€
1 34L.
Page501. Goal
Studentsunderstandtheconceptofproperfractionsandmixednumbers.2. Assessment Criteria
(Interest)Studentsexpressmixednumbersonanumberline.(Thinking)Studentsnoticethatmixednumberscanbeexpressedonanumberlinelikewholenumbers.(Expression)Studentsexpressmixednumbersonanumberlineandcomparerelativesize.(Knowledge)Studentsunderstandtheconceptofproperfractionsandmixednumbers.
3. Teaching Point Express mixed numbers on a number line
Helpstudentsbecomeawarethat
€
1 34,studiedinthepreviouslesson,canbe
expressedonanumberline,likewholenumbersanddecimalnumbers.Definition of proper fraction and mixed number
Properfractionsarefractionswhosenumeratorsaresmallerthantheirdenominators.Mixednumbersarefractionsexpressedbycombiningawholenumberandaproperfraction.Byplacingproperfractionsandmixednumbersona
numberline,studentswillbecomefurtherawareofthedifferencesbetweenproperfractionsandmixednumbersanddeepentheirunderstandingofthem.4. Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize; Assessment & Extra Support
1.Students understand that
€
1 34
can be expressed on a
number line and they understand mixed numbers as numbers. (Independent work) (K)“If the size of this square is 1, how do you
show
€
1 34
?”
(K)“Then where is the mark
for
€
1 34
on the number
line?” (K) “What fractions are indicated by a, b, c, d?"
Students express
€
1 34
on a
number line.
First, express
€
1 34
with the
square area illustration. Possible Reactions:
1)
€
1 34
is the size of 1 square
plus 3 out of 4 equal pieces of 1 square.
Express
€
1 34
on a number
line. Possible Reactions: 1) The marks on the number line divide 1 into 4 equal
parts, so
€
1 34
is three parts
after 1. Students read proper fractions and mixed numbers associated with points on the number line from textbook p.40
1) a-
€
14
2) b-
€
34
3) c-
€
2 24
Textbooks are closed. Teachers show the square and have students think
about how to express
€
1 34
.
(Interest) Students will express mixed numbers on a number line. Teachers show a number line and based on the structure of mixed numbers, put the mark on the number line for the whole numbers part. Then put the mark for the fractional part. (Expression) Students can express mixed numbers on a number line. Teachers have students understand the size of each scale on the number line from 0 to 1. It is useful for students to be able to read a fractional amount on number line.
(K) “Among these fractions, which fractions are less than 1? Which are greater than 1?” 2.Students will understand the definition of proper fractions and mixed numbers. (K) “Are proper fractions smaller than 1 or greater than 1? How about mixed numbers?” 3.Students work on 1) page 41. “Let’s find the mixed numbers.”
4) d-
€
3 14
Students categorize the fractions 1)-4) above and
€
1 34
into fractions that are
less than 1 and into fractions that are greater than 1. Possible reactions:
·fractions less than 1:
€
14
,
€
34
·fractions more than 1:
€
1 34
,
€
2 24
,
€
3 14
Students learn the definition of proper numbers and mixed numbers. “Proper fraction:” A fraction whose numerator is less than the denominator. “Mixed number:” A fraction that is made up of a whole number and a proper fraction. Students learn the fractions that are smaller than 1 are called proper fractions and the fractions that are greater than 1 are called mixed numbers. Students work on 1) page 41. Students use the definitions of proper fractions and mixed numbers to judge the fractions and to deepen their understanding of the concepts.
Teachers help students learn the definitions having students underline or circle the definitions in their textbooks or write them in their notebooks. (Knowledge) Students learn the concept of “proper fractions” and “mixed numbers.” (Knowledge) Students understand that mixed numbers can be expressed as the combination of the whole number part and the proper fraction part. (Thinking) As for integers and decimal numbers,
4.Students do practice problems.
Students work on questions 2) and 3) on page 41. Students understand that fractions can be compared like whole numbers and decimal numbers. Students can express an amount greater than 1 with mixed numbers
students realize they can judge the relative size of fractions.
5. Example of black board
Let’s express
€
1 34
on a number line!
Illustrationofnumberlineandpartitionedrectanglefromtextbookp.40Fractionsthatcorrespondtopointsa,b,c,d
a:
€
14b:
€
34c:
€
2 24d:
€
3 14
Fractions that are smaller than 1
€
14,
€
34
Fractions that are greater than 1
€
1 34
,
€
2 24,
€
3 14
Summarize Properfraction Afractionwithanumeratorsmallerthanthe
denominator Afractionsmallerthan1Mixednumber Afractionthatexpressesanintegerandaproper fractioncombined Afractionlargerthan1Page521. Goal Studentswillunderstandtheconceptofimproperfractions.Studentswillunderstandfractionsthatareequalinsizetowholenumbers.2. Assessment Criteria
(Interest)Studentswillconsidertherelationshipofthenumeratoranddenominatorinfractionsthatareequalinsizetowholenumbers.(Thinking)Studentswillnoticethatimproperfractions,likewholenumbers,expresshowmanyofaunit.
(Expression)Studentsareabletochangeimproperfractionstowholenumbers(Knowledge)Studentswillunderstandtheconceptofimproperfractions.
3. Teaching Point Express improper fractions on a number line.
Studentshavelearnedhowtoexpressproperfractionsandmixednumbersonanumberlineinthepreviouslesson.Here,theywilllearntherelationshipbetweenwholenumbersandfractionsbyexpressingonanumberlinefractions
suchas3or4piecesof
€
13;or2,3or4piecesof
€
14.
The definition of improper fractions Studentswilldefinefractionsthathavethesamenumeratorsand
denominatorsandfractionswithalargernumeratorthandenominatorasimproperfractions.Teachersshouldhelpstudentsclarifytheirunderstandingofthemeaningofimproperfractionsmoreclearlybydistinguishingthemfromproperfractionsandmixednumbers.4. Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize; Assessment & Extra Support
1.Students think about how
many m three
€
13
m, four
€
13
m are. (Independent
work) (K) “How many m are three
€
13
m, four
€
13
m?”
(K) “Let’s think about how
to express 1m and
€
113
m in
different ways.”
Students investigate how
many m three
€
13
m, four
€
13
m
are. (Possible reactions)
1) Three
€
13
m are the same
value as 1m and four
€
13
m
are the same value as
€
113
m.
Students compare the tape diagram and number line and try to find another way to express the points. 1) 1m can be expressed as
€
33
m.
2)
€
113
m can be expressed as
To get students’ interest, teachers show a tape diagram, divided into 3 equal parts and a number line. Teachers write the question on the black board or paper. Extra Support: Comparing the tape diagram and number line, help students realize they need to think about how
many
€
13
’s
(Thinking) Students notice that improper fractions, like whole numbers, are made up of so many units. Students notice that whole numbers and mixed numbers
2.Students learn the meaning of “improper fraction.” (K) “Are improper fractions larger or smaller than 1?” 3.Students do practice problems. 4.Students will investigate fractions made up of
€
43
m.
Students learn the definition of improper fraction. Improper fraction: A fraction whose numerator is the same as or greater than its denominator. Through pointing out on number line, students deepen understanding of the definition of improper fraction. (possible reactions) 1) It is more than 1 2) It is equivalent to or more than 1. Students work on question 1) page 42. Make sure numerators are larger than denominators. Students work on question 2) page 42. Make sure students judge fractions by the definition of improper fractions and clarify the concept of improper fractions. Students express proper and
can be expressed by improper fractions. Teachers have students underline the definition of proper fractions and improper fractions in their textbooks or write them in their notebook to help them understand the definitions clearly. (Knowledge) Students understand the concept of “improper fraction.” Teachers have students confirm the size of improper fractions visually by making use of number lines. Through ample use of the number line, students deepen their understanding of the definition of improper fractions, and understand the relationship to proper fractions and mixed numbers. Teachers show the number line scaled in fourths. Teachers make sure students
2,3,4…
€
14
’s, etc..
(K) “Let’s write proper and improper fractions made up
of 2, 3, 4….
€
14
’s.”
(K) “Let’s compare improper fractions which are equal to whole numbers and each other.” (K) “Let’s try 1) on page 42.”
improper fractions made up
of 2, 3, 4…
€
14
’s, etc..
Possible Responses
1)
€
24
,
€
34
,
€
44
,
€
54
….
2) It can go on forever. Students investigate the relationship between improper fractions and whole numbers. 1) Numerators can be divided evenly by denominators. 2) They are equal or 2 times, 3 times, etc.. Students work on 1) page 42.
know how many
€
14
’s there
are. (Interest) Students consider the relationship of numerator to denominator in fractions equivalent to whole numbers. Extra Support: Help students think about how many times as big the numerator is compared to the denominator. (Expression)Students change improper fractions to whole numbers.
5. Example of black board
Howmanymarethree
€
13m?Four
€
13m?
Summarize Improperfraction: Afractionwhosenumeratoristhesameasorgreaterthanits
denominator. Itisequalto1orgreaterthan1.
Let’swriteproperandimproperfractionsmadeupof2,3,4,…..
€
14’s.
Goal
Let’sinvestigatetherelationshipbetweenwholenumbersandimproperfractions.
Summarize
Animproperfractionisequaltoawholenumberifithasthesamenumeratorasdenominator.Orthenumeratoris2timesor3timesthedenominator.Page541. Goal
Studentswillunderstandhowtochangemixednumbersandimproperfractionsintoeachother.
2. Assessment Criteria
(Interest)Studentsareinterestedintherelationshipbetweenmixednumbersandimproperfractions.Theyarewillingtochangethemfromonetoanother.(Expression)Studentsareabletochangemixednumbersandimproperfractionsbackandforth.(Knowledge)Studentsunderstandhowtochangemixednumbersandimproperfractionsintoeachother.
3. Teaching Point Changing mixed numbers into improper fractions
Bythinkingabouthowmanyofaunitfractionthereare,studentsnoticethattheycanchangemixednumbersintoimproperfractions.Studentsneedtopayattentiontothedenominatorandlearntoconvertmixednumbersbymakinguseoftherelationshipbetweenimproperfractionsandwholenumbersstudiedinthepreviouslesson.
Changing improper fractions to mixed numbers
Usingtheirknowledgeofunitfractionsstudentsbecomefamiliarwithchangingimproperfractionsintomixednumbers.Teachersneedtoconfirmthatstudentsrealizethatwhenthedenominatorandnumeratorareequalthefractionisequalto1,andtoseethatthewholenumberportionofthemixednumberisdeterminedbyhowmany1’sthereare.4. Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize; Assessment & Extra Support
1.Students work on problems in which they change mixed numbers into improper fractions. (Independent work) (K) “Let’s think about how
to change
€
2 13
into an
improper fraction.”
(K) “How many
€
13
s do you
need to make
€
2 13
?”
Students think about how to
change
€
2 13
into an
improper fraction. Possible Reactions: 1) (Using a number line) 1
is 3 pieces of
€
13
, so it is
€
33
.
2) (Using an area illustration) We can say the same things. Students think about how
many
€
13
s they need to make
Textbooks are closed. Teachers show a number line and have students think
about how to express
€
2 13
.
Students notice that they needs a number line scaled
in
€
13
’s.
(Interest) Students will be interested in the relationship between mixed numbers and improper fractions and
(K) “ Is there a way to calculate?” 2.Summarize how to change mixed numbers into improper fractions. 3.Students work on practice problems. (K) “Let’s try the problems using what you have learned in this lesson.” 4.Students take up the challenge of changing improper fractions to mixed numbers. (K) “What do you have to
know to change
€
73
into a
€
2 13
.
1) (Using a number line) 7
pieces of
€
13
are
€
73
.
2) (Using an area
illustration) 7 pieces of
€
13
are
€
73
.
3) 1 is the same amount as
€
33
. So 2 pieces of
€
33
and
one piece of
€
13
total
€
73
.
4) (From the previous
lesson) 2 is expressed as
€
63
in fraction. So 2 and
€
13
total
€
7
3.
Students think about how to change mixed numbers into improper fractions by calculation. (Possible reactions) 1) We can multiply denominators and the whole number part of mixed numbers, then add numerators. 2) We can find the numerator by 3×2+1=7. Students learn how to find the numerator when changing mixed numbers into improper fractions. Students work on question 1) on page 43. Students will think about
willing to change them into one another. Through discussion, teachers have students grasp how to change mixed numbers to improper fractions. Teachers have students write in their notebooks to strengthen their understanding. (Expression) Students will be able to change mixed numbers and improper fractions. (Interest) Students will be interested in the relationship between mixed numbers and improper fractions and
mixed number?”
(K) “Let’s change
€
73
into a
mixed number.” (K) “ Do you know how to find the answer by calculation? 5. Students summarize how to change improper fractions into mixed numbers. 6. Students work on problems.
how to change
€
7
3 into a
mixed number.
1) How many
€
33
’s do you
need to make
€
73
?
2) How many 1’s and how much left over is there in
€
73
?
Students think about how to
change
€
7
3 into mixed
numbers. (Possible reactions)
1) It would be
€
2 13
. Because
€
7
3 includes 2 pieces of
€
33
.
2) It would be
€
2 13
. Because
€
7
3 includes 2 pieces of 1(
€
33
)
and left over is
€
13
.
Students learn how to change improper fractions into mixed numbers. Students work on problem 1) page 43.
willing to change them into one another. Teachers show a number line and have students scale
the number line into
€
13
’s
and express
€
7
3 on the
number line. Comparing to the number line, students think about
how many
€
33
(1)’s exist in
€
73
.
(Knowledge) Students will understand the relationship between improper fractions, mixed numbers, and whole numbers. (Expression) Students will be able to change mixed numbers and improper fractions.
5. Example of black board organization (contains illustrations not reproduced here)
Let’sthinkabouthowtochange
€
2 13intoimproperfractions.
Summary
Changemixednumbersintoimproperfractions
Let’sthinkabouthowtochange
€
7
3intomixednumbers.
∙Howmany1’s(
€
33)doyouneedtomake
€
7
3?
Summary Changeimproperfractionsintomixednumbers.Page561. Goal ‐Studentswillunderstandtheequivalentrelationshipbetweenproperfractions.‐Studentswillunderstandhowtocomparetherelativesizeoffractionswhosenumeratorsarethesame.2. Assessment Criteria
(Interest)Studentswillconsidertherelativesizeandequivalenceoffractionsmakinguseofanumberline.(Thinking)Studentswillunderstandthattheycancomparetherelativesizeoffractionsthathavethesamedenominatororthesamenumeratorbythinkingaboutunitfractions.(Expression)Studentscancomparevariousfractionsonanumberlineandtheycancomparetherelativesizeoffractionsthathavethesamenumerator.(Knowledge)Studentswillunderstandequivalentfractionsusinganareaillustration.
3. Teaching Point Fractions expressed on a number line
Makenumberlinesalignedat0,withintervalsof
€
12,
€
13,
€
14,
€
15,
€
16,
€
17,
€
18,
€
19,
€
110.
Havestudentsgraspthesizeofthefractionsandequivalentfractionsusingthesedifferentnumberlinesalignedatzero.
4. Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize; Assessment & Extra Support
1.Students will find
fractions equivalent to
€
12
.
(K) “Let’s express the colored parts as fractions.”
Students express the colored parts as fractions. Possible Reactions:
1) They are
€
12
,
€
24
,
€
510
.
2) All of them are half of the square but they are expressed as various fractions.
Using a number line, teachers explain that all of the colored parts are the
same size and
€
12
can be
expressed as various fractions such as
2.Student read and understand question 2 on page 44. (K) “What fractions are expressed by the intervals on each number line?” (K) “Among these, are there any fractions that are equal in size?” (K) “Let’s find the fractions that are equal in
size to
€
13
or
€
23
.”
3.Students read question 3 on page 45 and compare fractions to each other using a number line.
(K) “Which is bigger,
€
12
or
€
14
? And why?”
(K) “List fractions whose numerators are 1 in decreasing order.”
Students look for the fractions that are equivalent using a number line. Students look for the fractions that are equivalent
to
€
13
or
€
23
using a number
line. Students compare the size of
€
12
and
€
14
.
Possible Reactions:
1)
€
12
is greater than
€
14
on a
number line.
2)
€
12
is 1 out of 2 equal
pieces of 1.
€
14
is 1 out of 4
equal pieces of 1. So
€
12
is
greater than
€
14
.
Students compare the relative size of fractions whose numerators are 1.
1)
€
12
is the greatest one.
€
13,
€
14,
€
15,
€
16,
€
17,
€
18,
€
19,
€
110
is the
decreasing order. Students compare the size of
€
23
and
€
26
.
€
12
=
€
24
=
€
510
.
(Knowledge) Students will understand equivalent fractions referring to area illustrations. After finding equivalent fractions, teachers have students express them as math sentences such as
€
15
=210
or
€
13
=26
to
understand that various fractions can express the same amount. Teachers need to introduce equivalence and relative size of fractions on the number line but do not need to go into great depth. (Interest) Students consider relative size and equivalence of fractions using number lines. (Expression) Students can compare the size of fractions on a number line. And they can compare the relative size of fractions that have the same numerator. Teachers work on �1 using a number line and have students understand the
(K) “Which is bigger,
€
23
or
€
26
? And why?”
(K) “List fractions whose numerators are 2 in decreasing order.” 4. Summarize the contents of this lesson. 5.Students work on exercise.
(Possible reactions) 1) I see from the number line
that
€
23
is greater than
2) When 1 is divided into 3
equal pieces,
€
23
is 2 of the
pieces; when 1 is divided
into 6 equal pieces,
€
26
is 2 of
the pieces. Both of them have 2 pieces but the unit
fraction
€
13
is greater than
unit fraction
€
16
so
€
23
is
greater than
€
26
.
Students compare the size of fractions whose numerators are 2.
1)
€
23
is the greatest one.
€
24,25,26, 27,28,29, 210
are in
decreasing order. Students summarize that there are various fractions that are equivalent. In addition, they understand that the size of fractions can be compared. Possible Reactions: 1) Among the fractions that have the same numerator, the greater the denominator, the smaller the size of the fraction. Students work on the problem 1) on page 45. Making use of the summary of today’s lesson, students
relative size of fractions whose numerators are 1. Teachers summarize 1 and expand the lesson. Students pick up all of the fractions whose numerators are 1 and understand the relative size using a number line. Teachers work on 1, 2, 3 and develop the lesson. Students understand that for fractions that have the same numerator, the greater the denominator, the smaller the size of the fractions. At this level, it is difficult for students to convince themselves of the contents of this lesson logically, so teachers should use a number line to help them understand visually.
compare the size of fractions whose numerators are 3 and 4.
(Expression) Students can compare the various fractions on a number line. In addition, they can compare the relative size of fractions that have the same numerator. (Thinking) Students will understand how to compare the relative size of fractions with the same denominator and numerator using unit fractions.
5. Example of Black Board Organization
Let’sthinkaboutthesizeoffractions.Equivalent fractions
€
12
=
€
24
=
€
510
€
13
=26,23
=46,25
=410, 35
=610
Let’s compare the size of fractions
∙
€
12,
€
13,
€
14…..decreasinginthisorder
∙
€
23, 24,25….decreasinginthisorder.
Summarize Forfractionsthathavethesamenumerator,thegreaterthedenominator,the
smallerthesizeofthefraction.Page581. Goal
Studentsunderstandandcanperformadditionofproperfractionswhosedenominatorsarethesame(theanswersareimproperfractions).
2. Assessment Criteria
(Thinking)Studentswillnoticethatadditionofimproperfractionsthathavethesamedenominator(theanswersareimproperfractions)canbedonein
thesamewayasadditionforwholenumbersiftheypayattentiontotheconceptofunitfractions(Expression)Studentscanaddproperfractionsthathavethesamedenominator.(Theanswersareimproperfractions.)(Knowledge)Studentsunderstandhowtoaddproperfractionsthathavethesamedenominator.(Theanswersareimproperfractions.)
3. Teaching Point 1)UnitamountStudentsareexpectedtonoticeadditionofproperfractions,whichtheylearnedingrade3,canbeappliedtocalculationsingrade4.Soteachershavetoconfirmtheconceptofunitfractions.4.Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize; Assessment & Extra Support
1. Understand the contents of this lesson. (K) “What do you know about this number sentence? How would you answer it?” 2. Make a math sentence. (Independent work) (K) “Let’s think about what kind of math sentence is good to answer this
Referring to the illustration, students discuss the scene in the textbook and develop interest in solving it.
Shiori used
€
35
m² of
cardboard, and Kiyoshi used
€
45
m². How many m² of
cardboard did they use altogether? Possible reactions 1) The numbers used in the
question….Shiori used
€
35
m²
of cardboard, and Kiyoshi
used
€
45
m².
2) What we have to find out… How many m² of cardboard did they use altogether? Students think about a number sentence to answer how many m² of cardboard they used altogether.
Teachers show illustration so that students develop interest. Teachers motivate students to think about how to calculate proper fraction + proper fraction, a goal of this lesson. Teachers instruct them to underline the important amounts in this problem and to clearly identify what already known and what they have to find out. Textbooks are closed. For the students who are struggling with making number sentences, teachers can give them hints such as
question. Why?” 3.Think about how to calculate. (K) “How would you
calculate
€
35
+
€
45
?”
4.Summarize how to add fractions that have the same denominators. (K) “What is the common thing among those ways of solving the problem?” (K) “How do you do it when the answer is an improper fraction?” 5.Students work on practice problems.
Possible reactions:
1)
€
35
+
€
45
2) Use
€
35
m² and
€
45
m²
“altogether” so we can add them. Students understand the goal of this lesson. ·How to add fractions. Students think about how to calculate. (Possible reactions)
1)
€
35
is 3 pieces of
€
15
,
€
45
is
4 pieces of
€
15
. So
€
35
+
€
45
is 7
pieces of
€
15
. Therefore, the
answer is
€
75
.
2) We learned
€
35
+
€
15
=
€
45
in
grade 3. So we can make
€
35
+
€
45
=
€
75
.
3) Using the area of the
square, 7 pieces of
€
15
=
€
75
.
So the answer is
€
75
m².
4) I found the answer the
same way, but I changed
€
75
to
€
125
m².
5) I used a number line (shows illustration). Students summarize calculation process.
“if you replace
€
35
m² with 3
m²,
€
45
m² with 4 m², what
kind of number sentence can you make?” (Thinking) Students will notice that addition of improper fractions whose denominators are the same (the answers are improper fractions) can be operated on the same way as addition of whole numbers using the concept of unit fractions. All of the calculations can be done as in 2 on page 46. (Knowledge) Students understand how to add proper fractions that have the same denominator. (The answers are improper fractions.)
(Possible reactions)
1) How many
€
15
’s are there?
2) We can add 3 and 4 if we
notice the unit amount is
€
15
.
3) We can add numerators. 4) When adding fractions that have the same denominators, just add the numerators and leave the denominators as they are. When the answer is an improper fraction, students should change it into a mixed number or whole number. Students do question 1) on page 46.
(Expression) Students can add proper fractions that have the same denominators. (The answers are improper fractions.)
5. Example on Blackboard
Shioriused
€
35
m²ofcardboard,andKiyoshiused
€
45
m².Howmanym²of
cardboarddidtheyusealtogether?Math sentence
Addition
€
35
+
€
45
Let’sthinkabouthowtocalculate
€
35
+
€
45.
1) Thinkabouthowmany
€
15
’sexist.
2) Iaddedthenumeratorsinthesamewayasingrade3.
€
35
+
€
45
=
€
75
3) Finditoutusingareasquare.7piecesof
€
15=
€
75m²=
€
125m²
4) Finditoutusinganumberline.
Summary Whenaddingfractionsthathavethesamedenominator,justaddthe
numeratorsandleavethedenominatorasitis.
€
35
+
€
45
=
€
75=
€
125
Page601. Goal Studentsunderstandandcanperformsubtractionofproperfractionsfrommixednumbers.(Theintegerportionofthemixednumberis1andtheanswerisaproperfraction.)2. Assessment Criteria
(Interest)Studentswillunderstandhowtosubtractfractionsthathavethesamedenominators,relatingthewayofcalculationtowhattheylearnedbeforeforaddition.(Thinking)Studentswillnoticethatsubtractionofproperfractionsfrommixednumberscanbedonebythinkingabouthowmanyunitfractionsareineach,astheydidintheearlierstudyofaddition(Expression)Studentscansubtractfractionsthathavethesamedenominator.(Knowledge)Studentsunderstandhowtosubtractfractionsthathavethesamedenominators.
3. Teaching Point 1)Subtractionoffractionsthathavethesamedenominators.Itisimportantforstudentstofindtheirownwayofsubtracting,usingtheconceptofunitfractionsandoftheknowledgetheyhavealreadylearnedinaddition.4.Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize; Assessment & Extra Support
1. Understand the contents in this lesson. (K) “What do you know about this number sentence? How would you answer it?”
Referring to the illustration, students discuss the scene in textbooks for this number sentence and develop interest in solving it.
There is
€
125
kg of sugar. If
you use
€
45
kg, how many kg
will be left? 1) The numbers used in this
question….There is
€
125
kg of
Teachers show illustration and motivate students to think about how to subtract fractions that have the same denominators Teachers instruct them to underline the important part of the number sentence and help students understand what is already known in this question and what they need to figure out.
2 Make math sentence. (Self-solving) “What kind of number sentence is good to finding out how many kg of sugar will be left?” 3.Think about how to calculate. “How would you calculate
€
125
-
€
45
?”
“Which part of the number
sentence
€
125
-
€
45
is similar to
what you learned before in
sugar. And you use
€
45
kg.
2) What do students have to answer… How many kg will be left? Students think about the number sentence.
1)
€
125
-
€
45
.
2) We can subtract
€
125
-
€
45
because we want to find
out the remainder. Students will understand the goal of this lesson. ·How to subtract fractions. ·Can you subtract fraction in the same way as for addition? Students think about how to
calculate
€
125
-
€
45
.
(Possible reactions)
1) If we change
€
125
- into
€
75
,
we can make
€
75
-
€
45
Then, based on
€
15
, we can
subtract 4 from 7 and the remainder is 3. So the
answer is
€
35
.
2) Based on
€
15
, we can do 7-
4=3. So the answer is
€
35
kg.
Teachers have students close their textbooks. For the students who are struggling with making number sentences, teachers can give hints such as “if
you replace
€
125
kg with7kg,
€
45
kg with 4kg, what kind of
math sentence can you make?” Teachers have students write the goal of this lesson down in their notebooks to confirm it. For students who are struggling with making a number sentence, teacher can give hints such as “you
can change
€
125
into
€
75
,” or
“how many
€
15
s do you need
to make
€
75
or
€
45
?” Students
will think about how to calculate it. (Interest) Students will subtract fractions that have the same denominators, relating this to the method they learned before for addition. (Thinking) Students will notice that the subtraction of proper fractions from mixed numbers whose whole parts are 1 and whose answers are proper fractions, can be done using
addition?” 4.Summarize how to subtract fractions that have the same denominators. “What is common about the calculation?” 5.Work on problems. “How would you subtract fractions when the number to be subtracted (subtrahend) is a mixed number?”
3) Use square area illustration. 4) Use a number line. Students discuss the similarities to what they learned before in addition. 1) To find answer based on
€
15
.
2) To add/subtract fractions
based on
€
15
.
Students summarize how to subtract fractions that have the same denominators. 1) In any calculation, we use
€
15
as an unit amount.
·When subtracting fractions that have the same denominators, just subtract the numerators and leave the denominators as they are. Students work on 1) page 47. 1) When subtracted numbers (subtrahends) are mixed numbers, we have to change them into improper fractions. Then we can subtract only numerators based on the concept of unit fractions.
the method they learned before for addition. All of calculations can be done in the same way as 3 on page 47. (Knowledge) Students will understand how to subtract fractions that have the same denominators. (Expression) Students will subtract fractions that have the same denominators.
5. Example of Black Board
Thereis
€
125kgofsugar.Ifyouuse
€
45kg,howmanykgwillbeleft?
Math Sentence
€
125‐
€
45
Let’sthinkabouthowtocalculate
€
125‐
€
45.
1)Ifyouchange
€
125into
€
75,
€
75‐
€
45
2)Ifyouusebase
€
15,7‐4=3.Therearethree
€
15.Sotheansweris
€
35kg.
3)Useanillustration.4)Useanumberline.What is the common way to add fractions?
∙Weusebase
€
15asunitquantityandthinkabouthowmany
€
15sdoweneedtomake
€
75and
€
45.
Summarize
∙Change
€
125into
€
75
Whensubtractingfractionsthathavethesamedenominators,justsubtractthenumeratorsandleavethedenominatorsastheyare.
€
75‐
€
45=
€
35.
€
35kg
Page621.Goal Studentswillunderstandhowtoaddmixednumbersandbefamiliarwithit.2. Assessment Criteria
(Interest)Studentswillrelatemixednumberstoproperfractionswhendoingadditionoperations.(Thinking)Studentswillnoticethattheycanaddmixednumbersastheyaddedproperfractions.(Expression)Studentscanaddmixednumbers.(Knowledge)Studentsunderstandhowtoaddmixednumbers.
3. Teaching Point Addition of mixed numbers.
Basedonadditionofimproperfractionsthathavethesamedenominators,studentswilllearnthetwowaysofaddition.Oneinvolvesseparatingmixednumbersintothewholenumberspartsandthefractionalpartsthenfindingthesumofthewholenumberspartsandthefractionalpartsseparatelyandfinallycombiningthosepartstogether.Theotheristochangethemixednumbersintoimproperfractionsthencalculate.
4. Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize; Assessment & Extra Support
1.Think about how to calculate. (K) “Let’s think about how
to calculate
€
2 35
+115
.”
2.Summarize how to add mixed numbers. (K) “How would you calculate mixed numbers that have the same denominators?”
Students understand the goal of this lesson. ·How to add mixed numbers? Students think about how to calculate. (Possible reactions) 1) Find the sum of the whole number parts and the fractional parts, then combine them. 2) Change the mixed numbers into improper fractions and calculate. 3) Calculate using an area illustration. Students summarize how to add mixed numbers that have the same denominators. ·Combine the sum of the whole number parts and the fractional parts. ·Change the mixed numbers into improper fractions and calculate.
Teachers have students write the goal down in their notebooks to make it clear. For the students who are struggling with how to solve this, hand out a paper with the area illustration on page 48 so that students can relate mixed numbers to an area illustration. (Interest) Students will think about how to add mixed numbers, relating it to addition of proper fractions. (Thinking) Students will notice that addition of mixed numbers can be done like addition of proper fractions. Teachers check that students understand that the both calculations are based on addition of proper fractions. If you change mixed numbers into improper fractions to calculate, you have to change the answer into mixed numbers again. Many students are likely to make a mistake when they are changing the answer back into mixed numbers. But we do not have to change mixed numbers into improper fractions all the time. Teachers should teach the benefit of calculation, which is that the whole numbers parts and the fractional parts are
3.Work on exercise.
Students work on 1) page 48. ·Think about how to add whole numbers. Students work on 2) page 48. ·Students think about how to operate the answer of mixed numbers when its fractional parts become improper fractions.
added/subtracted separately. Teachers check that students understand that if the fractional parts become improper fractions in the answer, put appropriate numbers of unit fractions on whole numbers parts. (Expression) Students can add mixed numbers.
5. Example of Black Board
Let’sthinkabouthowtocalculate
€
2 35
+115.
1)Findthesumofthewholenumberpartsandthefractionalpartsthencombinethem.2)Changethemixednumbersintoimproperfractionsthencalculate.3)Findtheanswerusinganareaillustration.Summary 1)Findthesumofthewholenumberpartsandthefractionalpartsandcombinethem.2)Changethemixednumbersintoimproperfractionsandcalculate.Page641. Goal Studentswillunderstandhowtosubtractmixednumbersfrommixednumbersandcalculate.2. Assessment Criteria
(Interest)Studentswillthinkabouthowtosubtractmixednumbers,relatingittotheadditionofmixednumbersorsubtractionofproperfractions.(Expression)Studentscansubtractmixednumbers.(Knowledge)Studentswillunderstandhowtosubtractmixednumbers.
3. Teaching Point Subtraction of mixed numbers that have the same denominators.
Usingwhattheylearnedaboutadditionandsubtractionofmixednumbersthathavethesamedenominators,studentsshouldfindtheirownwayofsubtracting.Wecanseparatethemixednumbersintothewholenumberpartsand
thefractionalpartsthencalculate.Orwecanchangethemixednumbersintoimproperfractionsbeforecalculating.
4. Lesson Lesson and Key Questions (K)
Learning Activities and Reactions
Points to Emphasize; Assessment & Extra Support
1.Think about how to calculate. (K) “Let’s think about how
to calculate
€
2 45−135
.”
2.Summarize how to calculate. (K) “Let’s review how to
calculate
€
2 45−135
.”
3.Work on exercise.
Students understand the goal of this lesson. Students think about how to calculate. 1) Find the difference of the whole number parts and the difference of the fractional parts then combine them. 2) Change the mixed fractions into improper fractions then calculate. 3) Find the answer using a number line. Students summarize how to subtract mixed numbers that have the same denominators. 1) Find the difference of the whole number parts and the difference of the fractional parts and combine them. 2) Change the mixed fractions into improper fractions and calculate. Solve problem set (1) on p. 49. - Think about how to do it by adding the whole numbers Solve problem set (2) on
Teachers check that students understand that subtracted parts and parts subtracted from are mixed numbers and that is the difference between this lesson and previous lesson. For the students who are struggling with how to find the solution, hand out a paper with the area illustration on page 49, so that students can relate mixed numbers to an area illustration. (Interest) Students will think about how to subtract mixed numbers, relating them to previous learning about mixed numbers addition or proper fractions subtraction. Teachers check that students understand that all of the calculations are based on the rule of the previously learned subtractions. (Knowledge) Students will understand how to subtract mixed numbers. Teachers explain to students that they can calculate without changing mixed numbers into improper fractions.
p.49 -Think about how to do mixed number addition when the fractional parts add to an improper fraction.
Teachers have students notice that they can take the same way of previous subtraction, which subtract improper fraction from mixed number whose whole part is 1. (Expression) Students can subtract mixed numbers.
5. Examples on blackboard
Let’sthinkabouthowtocalculate
€
2 45−135.
1)Findthedifferenceofthewholenumberpartsandthedifferenceofthefractionalpartsandcombinethem.2)Changethemixedfractionsintoimproperfractionsandcalculate.Summary ∙Findthedifferenceofthewholenumberpartsandthedifferenceofthefractionalpartsandcombinethem.∙Changethemixednumbersintoimproperfractionsandcalculate.
Let’sthinkabouthowtocalculate
€
4 57− 2 67.
1)Findthedifferenceofthewholenumberpartsandthedifferenceofthefractionalpartsthencombinethem.Butwecannotsubtractfractionalpartsfromeachother.So:
Change
€
4 57into
€
3127(3+
€
157)
2)Changethemixedfractionsintoimproperfractions.
€
4 57− 2 67
Howtocalculate
€
5 −1 34?
1)Change5into
€
4 44.
2)Changemixednumbersintoimproperfractions.