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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!