Page 33 - Start Up Mathematics_7

1 2 5 7 1 2 4 3
2. Arrange in ascending order: (a) , , , (b) , , ,
3 3 6 9 2 3 5 4
7 5 13 11 3 9 7 17
3. Arrange in descending order: (a) , , , (b) , , ,
9 6 18 15 5 10 15 20
4. Find the sum of the following:
4 3 2 7 5 3 3 7 4
(a) 3 + (b) + + (c) + + 4 (d) 1 + 2 + 3
5 5 15 10 6 4 5 10 15
5. Find the difference of the following:

1
6
(a) 3 – (b) 5 3 – 2 2 (c) 3 – 7 (d) 8 – 15
7 10 15 5 15 3 7
3
6. What should be added to 6 to get 9?
4
3
7. What should be subtracted from 10 to get 3 ?
4
5 3
8. Jack and Jill took 10 minutes and 13 minutes respectively to complete an assignment.
11 7
Who completed the assignment faster? By how much time?

5 3
9. Amit covered 7 km in 2 hours on bicycle and 4 km in another 1 hour on foot. Find the
12 8
total distance covered by Amit in 3 hours.
1 1
10. The length and breadth of a rectangular room is 7 m and 5 m. Find the perimeter of the
6
2
room.
3
11. On a TV channel, a popular film lasted for 3 hours. Out of this time the commercial
4
1
advertisements were for 1 hour. What was the actual duration of the film?
4
A
5 3
12. Find the perimeter of (a) ∆ ABE, (b) rectangle BCDE in 2 cm 2 cm 3 cm
3
5
the given figure. Whose perimeter is greater? B 4 E
5 cm
4
C D

Multiplication of Fractions

We have learnt how to add or subtract fractions, but in many cases we need to multiply fractions.
Consider the case of Sharda, a fruit vendor who bought 16 boxes each containing 20 apples from
the wholesale fruit market. After reaching home, she found that the fruit merchant has cheated
1
her, as in each box of the apples were rotten. How many apples were rotten? How many apples
4
were in good condition?
4
Mr Sharma bought kg of sweets for the guests expected next morning. By the same evening
5
1
he found that his son and daughter had of the sweets. How much sweet was left for the guests?
2
To get answers of all such problems we need to learn multiplication of fractions.

25