m4(3) r ppt -mixed number

FRACTION

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.18

I take 2 slicesof the pizza.

I take 1 sliceof the pizza.

+ =28

38

18

of the pizza is given away altogether.38

How much of the pizza is left?

- =38

58

88

of the pizza is left.58

+ =38

88

58

Let’s look at this strip of paper. Ithas been divided into 9 equal parts.

of the paper iscoloured blue.

49

of the paper iscoloured orange.

39

What fraction of the paper is coloured?

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

+ =39 9

49

- =9 9

99

7

7 2

Related fractions

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

and are related fractionsas 3 is a factor of 6.

16

23

Let us add the 2 fractions, and .16

23

46

23 =

X 2

X 2

23

16

46

16

6

16

23

+

16

46

= +

5=

How do we subtract from ?710

25

Here is of an apple pie.

Now, let’s take away of the pie.

710

25

410

25 =

X 2

X 2

is the same as .410

25

I take away of the pie.410

10

25

710

-

410

710

= -

3=

Mixed numbers

I have 3 mooncakes.I have of a mooncake.

12

12

3

123 + = 1

23

There are 3 mooncakes altogether.12

whole number part

fractional part

123

Look at the mooncakes below.

231 + = 2

31

whole number part

fractional part

231

There are 1 mooncakes altogether.23

23

1

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

whole number part and a fractional part.

23

12

Improper fractions( pecahan tak wajar)

or55

1

or65

15

1

or75

25

1

or85

35

1

15

25

35

45

Lihat pecahan di bawah.

There are 6one-fifths in .1

51

Pecahan tak wajar boleh di nyatakan dalam bentuk nombor bulat dan pecahan wajar iaitu Nombor Bercampur.

, , dan adalah improper fractions (pecahan tak wajar).65

75

55

85

In an improper fraction, the numerator is

greater than or equal to the denominator.

(PECAHAN TAK WAJAR, PENGANGKANYA LEBIH BESAR DARI PENYEBUT)

Changing mixed numbers to improper fractions

Change into an improper fraction.23

3

23

3

113

Here isanother way.

There are 11 thirds in .23

3

3

233= +

11=

23

3

23

= +93

13

223

213

3 23

3

113

103

93

83

73

63

2 3

Changing improper fractions to mixed numbers

Express as a mixed number.94

Here isanother way.

There are 9 quarters in .14

2

14

124

134

1 14

2

94

84

74

64

54

44

1 2

94

14

2

14

= +

=

94

14

= +2

84

14

2

Look at the diagram below.

Try these.

113

123

1 13

2

73

63

53

43

33

230

2

13

33

= 43

= 23

1 = 13

2 = 13

1153

73

We have divided these 9 sweets into 3 equal groups.

Each group is of 9.13

What is of 9?23

is 2 groups out of 3 groups.23

of 9 is 6.23

13 of 9

13 of 9

13 of 9

Fraction of a set

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

4 equal groups. Each group is of 12.14

What is of 12?34

is 3 groups out of 4 groups.34

of 12 is 9.34

14 of 12

14 of 12

14 of 12

14 of 12

Product of a fraction and a whole number

1234

x 364

3 x 124

= =

9=

1. Find the value of x 12.43

So, x 12 is the same as of 12.43

43

Recall

43 of 12 is 9.

2. What is of 5?43

534

x 154

3 x 54

= =

3= 34

3. What is 5 x ?43

534

x 154

5 x 34

= =

3= 34

Word problems

39

13 =

X 3

X 3

2. The mass of Box A is kg. The mass of Box B is kg.31

95

(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.98

13

(a) + = +

=

59

39

59

89

Box B is kg heavier than Box A.92

59

(b) - = -

=

13

59

39

29

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

25

2050 =

÷ 10

÷ 10

50 – 30 = 20

52 of the burgers were chicken burgers.

12023

x 2 x 1203

=

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?

23

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.

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

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

15

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.

Hereis oneway.

5515

x 1 x 555

=

11=

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

Step 2Find the number of stamps he had left.

He had 44 stamps left.

Let’s tryanotherway.

5He had of his stamps left.4

115

- = -

=

55

15

45

5545

x 4 x 555

=

44=

We can add or subtract fractions with the same denominators.

Example:37

+ = , 47

17

310

+ = + ,

=

410

310

710

25

28

- 38

58

=

13

- = -

=

89

39

59

89

A mixed number has a whole number part and a fractional part.

Example: 2 and 3 are mixed numbers.14

12

In an improper fraction, the numerator is greater than or equal to

the denominator.

Example: , and are improper fractions.33

75

1110

Wrap-Up!

1

10

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

Example: 2 = , = 3, = 135

135

124

1110

725

x 2 x 75

=

=

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:

145

= 2 45

Wrap-Up!