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ROSE MARIE C. CALDERON
4TH YR BSED - MATH
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DEFINITION OF TERMS
RATIONAL NUMBERS
- Any number that can be made by
dividing one integer by another. Theword comes from "ratio".
- Is a number that can be in the form p/qwhere pandqare integers andqis not
equal to zero.
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p q p / q =
1 1 1/1 11 2 1/2 0.5
55 100 55/100 0.55
1 1000 1/1000 0.001
253 10 253/10 25.3
7 0 7/0No! "q"can't be
zero!
Examples:
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WHATAREFRACTIONS?
Fractions are for counting PART of something
The denominator
tells us how many
pieces something
is cut into.
The numerator
tells how manyfractional pieces
there are
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BASIC FRACTIONS
A fraction is part of an entire object.
1/4 is
pink
1/2 is
pink
3/4 is
pink
4/4 orone whole
is pink
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TOADDFRACTIONSWITHTHE
SAMEDENOMINATOR
Keep the common denominatorand add the numerator.
Example: 2/5 + 1/5= 3/5
Example: 4/10 + 3/10= 7/10
Notice that the denominator doesnot change, you only add thenumerator!
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ADDING FRACTIONSWITHCOMMON
DENOMINATORS
8
4
8
3
8
7
+ =
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TRYSOME!!!
1.) 1/3 + 1/3 =
2.) 3/8 + 4/8 =
3.) 1/10 + 6/10 =
4.) 1/5 + 2/5 =
5.) 24/50 + 20/50 =
6.) 6/13 + 6/13 =
7.) 2/45 + 12/45 =
8.) 8/90 + 15/90 =
2/3
7/8
7/10
3/5
49/50
12/13
14/45
23/90
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ADDINGFRACTIONSWITHDIFFERENT
DENOMINATORSISALITTLEDIFFERENT
You must first change the
fraction before you can addfractions.
The fractions must have thesame denominators to add
them.
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ADDING FRACTIONSWITHDIFFERENT
DENOMINATORS
Problem:
You cant add fractions with differentdenominators without getting them ready first.They will be ready to add when they havecommon denominators
Solution:Turn fractions into equivalent fractions with acommon denominator that is find the LowestCommon Multiple (LCM) of the two
denominators
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FINDINGTHE
LOWEST COMMON DENOMINATOR
The lowest common multiple of two numbers is
the lowest number in BOTH lists of multiples
3
1
2
1
Multiples of 2 are 2, 4, 6, 8, 10Multiples of 3 are 3, 6, 9, 12,
What is the lowest commonmultiple?
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FINDINGTHE
LOWEST COMMON DENOMINATOR
The lowest common multiple of two numbers is
the lowest number they will BOTH divide into
3
1
2
1
2 divides into 2, 4, 6, 8..3 divides into 3, 6, 9.
What is the lowest number 2 and 3both divide into?
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+The Lowest Common Multiple of 2 and 3 is 6 so turn all fractions into sixths
6
5
6
2
6
3
2
2
3
1
3
3
2
1
You cant add fractions with
different denominators
Special form of 1
3
1
2
1
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10
9
10
4
10
5
5
2
2
1
Lowest common denominator is 10 so make all fractions tenths
11
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4
1
3
1
Turn both fractions into twelfths
12
7
12
3
12
4
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3
2
7
3
What is the lowest numberBOTH 3 and 7 divide into?
Hmmmmm??????It is 21. So that is mycommon denominator
21
?
21
?
What special formof 1 will change 7to 21. Hmmmm?
It is 3/3
So I multiply3/7 by 3/3
3
3
What specialform of 1 will
change 3 to 21.Hmmmm?
It is 7/7So I multiply2/3 by 7/7
7
7
Now 3x3=9 and 2x7=14Now I know the new
numerators
21
14
21
9
Finally the fractions are READYto add. I just have to add the
numerators 9+14=23
21
21
21
23
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ADDING MIXED
NUMBERSBasic concepts and methods
for adding mixed numbers.
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DEFINITION
Mixed Number = A mixednumber is a whole number with
a fraction attached.
Example = 3 4/5, This isread as three and four fifths.
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ADDING MIXED NUMBERS Separate the fraction and the whole number sections,
add them separately and recombine at the end
2
2
1
3
1
5
6
57
76
5
22
1
3
1
5
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