Page 23 - Maths Skills - 8

Rational Numbers 21

5. Simplify.

8 3 3 11 5 16 21 6 4 9 4 7 64

(i) (ii) 21 (iii)
5 2 16 10 3 9 30 11 7 12 3 8 21
6. Divide the following.
8 90 − − 3 72 60
(i) by (ii) by (iii) by − 20
− 4 36 4 −16 99
− 33 1 26 13
(iv) 0 by (v) − 8 by (vi) by
53 2 15 5
7. Verify the following.

3 5 5 3 5 12 7 5 12 7
(i) (ii)
7 9 9 7 7 13 18 7 13 18
15 3 12 15 3 15 12

(iii)
4 7 5 4 7 4 5
8. Subtract the additive inverse of from the multiplicative inverse of 5 14 .
7

8 7 3
9. What should be added to 1 3 to get 6 ?

3 5 20
− 5 3
10. The sum of two rational numbers is . If one of the numbers is , find the other.
11 13
− − 5 11
11. What should be subtracted from to get ?
6 9
1 1
12. The cost of 7 metres of fabric is ` 30 . Find the cost of 12 metres of fabric.
3 4

1
13. 20 plants in a garden are watered by 7 litres of water. How much water is required by each plant?
2
14. The product of two rational numbers is − 5 . If one of them is 4 , find the other.
16 18
1 1
15. A container of capacity 5 litres takes 20 seconds to fill. What time will be taken by a container of
2 3
1
capacity 17 litres to fill completely at the same speed?
2

16. Simplify: 2 1 3 1 5 6 2 7 .
3 2 7 15

RATIONAL NUMBERS BETWEEN TWO RATIONAL NUMBERS
As we know that there is no integer between two consecutive integers. For example; –3 and – 4 have no integer
lying between them. In case of rational numbers, we can always find a rational number between two rational
numbers. It also suggests that between any two rational numbers, we can find infinite rational numbers.