Page 78 - Start Up Mathematics_5

EXERCISE 4.5

1. Simplify the like fractions.
4 2 1 8 3 5 13 7 3
(a) + + (b) – + (c) – +
9 9 9 11 11 11 18 18 18

(d) 32 + 8 – 21 (e) 29 – 11 – 9 (f) 21 + 2 – 11
45 45 45 34 34 34 39 39 39

2. Simplify the following fractions.
2 1 3 7 1 4 11 1
(a) 3 + 2 + 1 (b) 4 + 2 + 1 (c) 5 – 2 + 3
5 3 5 9 6 9 13 2

7 5 1 1 3 1
(d) 6 – 1 – 2 (e) 3 + 2 – 4 (f) 7 + 2 – 3
8 6 2 3 4 2
Word Problems

Example 24: Anshu ate 1 of a cake while her brother ate 2 of the cake. How much cake
3 5
did they eat together? How much cake is still left?

Solution: Anshu’s share of cake = 1
3

Her brother’s share of cake = 2
5

Total cake eaten = 1 + 2 = 5 + 6
3 5 15 15

= 5 + 6 = 11 Remember
15 15 In fractions, the whole
11 15 – 11 4 quantity is considered as 1.
Cake left = 1 – = =
15 15 15
11 4
Thus they ate of the cake and of the cake is left.
15 15
1
2
Example 25: Sahil had a jug filled with 3 litres of juice. He drank 1 litres of juice. How
5 5
much juice is left in the jug?
1
Solution: Total juice in the jug = 3 litres
5
2
Amount of juice Sahil drank = 1 litres
5
1
Amount of juice left = 3 – 1 2 litres
5 5

= (3 × 5) + 1 – (1 × 5) + 2
5 5

= 15 + 1 – 5 + 2
5 5

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