Home >Documents >tambah&tolak pecahan

tambah&tolak pecahan

Date post:03-Apr-2018
Category:
View:229 times
Download:0 times
Share this document with a friend
Transcript:
  • 7/28/2019 tambah&tolak pecahan

    1/26

    FRACTION

  • 7/28/2019 tambah&tolak pecahan

    2/26

    Without renaming

    Adding and subtracting fractions

    Fractions with the same denominator are known as like fractions.

    Look at this pizza. It is cut into 8 equal

    slices. 1 slice is of the pizza.1

    8

    I take 2 slicesof the pizza.

    I take 1 sliceof the pizza.

    + =2

    8

    3

    8

    1

    8

    of the pizza is given away altogether.3

    8

  • 7/28/2019 tambah&tolak pecahan

    3/26

  • 7/28/2019 tambah&tolak pecahan

    4/26

    Lets look at this strip of paper. Ithas been divided into 9 equal parts.

    of the paperis

    coloured blue.

    4

    9

    of the paper iscoloured orange.

    3

    9

    What fraction of the paper is coloured?

    What fraction of the paper is not coloured?Try these.

    + =3

    9 9

    4

    9

    - =9 9

    9

    9

    7

    7 2

  • 7/28/2019 tambah&tolak pecahan

    5/26

    Related fractions

    Related fractions have 1 denominator that is a factor of the other.

    and arerelated fractionsas 3 is a factor of 6.

    1

    6

    2

    3

  • 7/28/2019 tambah&tolak pecahan

    6/26

    Let us add the 2 fractions, and .1

    6

    2

    3

    4

    6

    2

    3=

    X 2

    X 2

    2

    3

    1

    6

    4

    6

    1

    6

    6

    16

    23

    +

    1

    6

    4

    6= +

    5=

  • 7/28/2019 tambah&tolak pecahan

    7/26

    How do we subtract from ?7

    10

    2

    5

    Here is of an apple pie.

    Now, lets take away of the pie.

    7

    10

    25

    4

    10

    2

    5 =

    X 2

    X 2

    is the same as .4

    10

    2

    5

    I take away of the pie.

    4

    10

    10

    25

    710

    -

    4

    10

    7

    10= -

    3=

  • 7/28/2019 tambah&tolak pecahan

    8/26

    Mixed numbers

    I have 3 mooncakes.I have of a mooncake.

    1

    2

    1

    23

    1

    23 + =

    1

    23

    There are 3 mooncakes altogether.1

    2

    whole number part

    fractional part

    12

    3

  • 7/28/2019 tambah&tolak pecahan

    9/26

    Look at the mooncakes below.

    23

    1 + = 23

    1

    whole number part

    fractional part

    2

    31

    There are 1 mooncakes altogether.23

    2

    3

    1

    Numbers like 3 and 1 are mixed numbers. A mixed number has a

    whole number part and a fractional part.

    2

    3

    1

    2

  • 7/28/2019 tambah&tolak pecahan

    10/26

    Improper fractions

    or5

    51

    or65

    15

    1

    or7

    5

    2

    5

    1

    or8

    5

    3

    51

    1

    5

    2

    5

    3

    5

    4

    5

    Look at the fractions below.

    There are 6one-fifths in .

    1

    51

  • 7/28/2019 tambah&tolak pecahan

    11/26

    An improper fraction can be expressed as a whole number or a mixed number.

    , , and are improper fractions.6

    5

    7

    5

    5

    5

    8

    5

    In an improper fraction, the numerator is

    greater than or equal to the denominator.

  • 7/28/2019 tambah&tolak pecahan

    12/26

    Changing mixed numbers to improper fractions

    Change into an improper fraction.2

    33

    2

    3

    3

    11

    3

    Here isanother way.

    There are 11 thirds in .

    2

    33

    3

    2

    33= +

    11=

    2

    33

    23= +93

    1

    32

    2

    32

    1

    332

    33

    11

    3

    10

    3

    9

    3

    8

    3

    7

    3

    6

    3

    2 3

  • 7/28/2019 tambah&tolak pecahan

    13/26

    Changing improper fractions to mixed numbers

    Express as a mixed number.9

    4

    Here isanother way.

    There are 9 quarters in .

    1

    42

    1

    412

    413

    411

    42

    9

    4

    8

    4

    7

    4

    6

    4

    5

    4

    4

    4

    1 2

    9

    4

    1

    4

    2

    1

    4= +

    =

    9

    4

    1

    4= +2

    8

    4

    1

    42

  • 7/28/2019 tambah&tolak pecahan

    14/26

    Look at the diagram below.

    Try these.

    11

    31

    2

    31

    1

    32

    7

    3

    6

    3

    5

    3

    4

    3

    3

    3

    2

    30

    2

    1

    3

    3

    3=

    4

    3= 2

    31 =

    1

    32 =

    1

    311

    5

    3

    7

    3

  • 7/28/2019 tambah&tolak pecahan

    15/26

    We have divided these 9 sweets into 3 equal groups.

    Each group is of 9.13

    What is of 9?2

    3

    is 2 groups out of 3 groups.23

    of 9 is 6.2

    3

    1

    3of 9

    1

    3of 9

    1

    3of 9

    Fraction of a set

  • 7/28/2019 tambah&tolak pecahan

    16/26

    Look at the 12 candies below. It has been divided into

    4 equal groups. Each group is of 12.1

    4

    What is of 12?34

    is 3 groups out of 4 groups.34

    of 12 is 9.3

    4

    1

    4of 12

    1

    4of 12

    1

    4of 12

    1

    4of 12

  • 7/28/2019 tambah&tolak pecahan

    17/26

    Product of a fraction and a whole number

    123

    4x

    36

    4

    3 x 12

    4= =

    9=

    1. Find the value of x 12.4

    3

    So, x 12 is the same as of 12.4

    3

    4

    3

    Recall

    4

    3 of 12 is 9.

  • 7/28/2019 tambah&tolak pecahan

    18/26

    2. What is of 5?4

    3

    53

    4x

    15

    4

    3 x 5

    4= =

    3=3

    4

  • 7/28/2019 tambah&tolak pecahan

    19/26

    3. What is 5 x ?4

    3

    53

    4x

    15

    4

    5 x 3

    4= =

    3=3

    4

  • 7/28/2019 tambah&tolak pecahan

    20/26

    Word problems

    3

    9

    1

    3 =

    X 3

    X 3

    2. The mass of Box A is kg. The mass of Box B is kg.3

    1

    9

    5

    (a) What is the total mass of the 2 boxes?

    (b) How much heavier is Box B than Box A?

    The total mass of the 2 boxes is kg.9

    8

    1

    3(a) + = +

    =

    5

    9

    3

    9

    5

    9

    8

    9

    Box B is kg heavier than Box A.9

    2

    5

    9(b) - = -

    =

    1

    3

    5

    9

    3

    9

    2

    9

  • 7/28/2019 tambah&tolak pecahan

    21/26

    4. Mrs Jones made 50 burgers. 30 of them were fish burgers and the rest werechicken burgers. Express the number of chicken burgers as a fraction of thenumber of burgers made.

    2

    5

    20

    50 =

    10

    10

    50 30 = 20

    52 of the burgers were chicken burgers.

  • 7/28/2019 tambah&tolak pecahan

    22/26

    1202

    3x

    2 x 120

    3=

    80=

    7. Mr Samson had 120 teddy bears in his toy store. He sold of them

    at $12 each. How much money did he receive?

    2

    3

    Step 1 Find the number of teddy bears sold.

    He sold 80 teddy bears.

    Step 2Find how much money he received.

    80 x 12 = 960

    He received $960.

  • 7/28/2019 tambah&tolak pecahan

    23/26

    8. My brother had 55 stamps in his stamp collection. He gave of

    his stamps away. How many stamps did he have left?

    1

    5

    Step 1Find the number of stamps given away.

    My brother gave away 11 stamps.

    Step 2Find the number of stamps he had left.

    55 11 = 44

    He had 44 stamps left.

    Hereisoneway.

    551

    5x

    1 x 55

    5=

    11=

  • 7/28/2019 tambah&tolak pecahan

    24/26

    Step 1Find the fraction of stamps that he had left.

    Step 2Find the number of stamps he had left.

    He had 44 stamps left.

    Lets tryanother

    way.

    5He had of his stamps left.

    4

    11

    5

    - = -

    =

    5

    5

    1

    54

    5

    5545 x 4 x 555=

    44=

  • 7/28/2019 tambah&tolak pecahan

    25/26

    We can add or subtract fractions with the same denominators.Example:

    3

    7+ = ,

    4

    7

    1

    7

    3

    10+ = + ,

    =

    4

    10

    3

    107

    10

    2

    5

    2

    8-

    3

    8

    5

    8=

    1

    3- = -

    =

    8

    9

    3

    95

    9

    8

    9

    A mixed number has a whole number part and a fractional part.Example: 2 and 3 are mixed numbers.

    1

    4

    1

    2

    In an improper fraction, the numerator is greater than or equal tothe denominator.

    Example: , and are improper fractions.3

    3

    7

    5

    11

    10

    Wrap-Up!

  • 7/28/2019 tambah&tolak pecahan

    26/26

    1

    10

    A mixed number can be expressed as an improper fraction. An improperfraction can be expressed as a whole number or a mixed number.

    Example: 2 = , = 3, = 13

    5

    13

    5

    12

    4

    11

    10

    72

    5

    x2 x 7

    5

    =

    =

    When we find the product of a fraction and a whole number, we

    multiply the whole number to the numerator. We then write the

    product over the denominator.

    Example:

    14

    5

    = 24

    5

    Wrap-Up!

Embed Size (px)
Recommended