Page 26 - ICSE Math 7

PRACTICE TIME

1. If A = {1, 2, 3, 4, …}, find whether A is closed under the following operations.

(a) addition (b) subtraction (c) multiplication (d) division
2. If X = {–5, –4, –3, –2, –1, 1, 2, 3, 4, 5} and x, y ∈ X, find whether X is closed under the operations
performed on x and y.
(a) x + y (b) x – y (c) x × y

3. Which is the smallest integer greater than 8 and greatest integer less than 8?
4. Find the following between –6 and 6.
(a) Natural numbers (b) Whole numbers (c) Integers

5. Find the products in each case.
(a) (–16) × (–4) × (–3) (b) (–10) × (4) × 0 × (–36) (c) (–12) × (–5) × (–2) × (–10)
6. Simplify using suitable properties.

(a) 12 × (–3) + 5 × (–3) (b) (–10) × (–7) + (–10) × (–3)
7. Find the value of the following.
(a) 4 × (–5) × (–6 – 4) × 3 (b) (–25) × (–4) × (10 – 21) × 11
(c) 8 × 12 × (20 – 9) × 6 (d) (–11) × 3 × (–6) × (–15)

8. Simplify the following.
(a) 42 – 36 ÷ [ 3 of {2 × (16 ÷ 3 + 1) – 6}] (b) 42 of (21 – 7 + 7 × 3)

(c) 12 – [8 –{9 – (7 – 6 – 5)}] (d) 6 of [{12 – (36 ÷ 5 – 1) + 3} ÷ 2]
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9. Simplify 2a – {3b + 6c ÷ 2c – (4a – 2b)} and find its value for a = 2, b = 3 and c = 1.
10. Represent the following on a number line.
(a) Integers greater than –4 and less than 0

(b) Integers greater than –1 and less than or equal to 1
11. Morning temperature on a particular day of October in Kashmir was recorded as 3.5ºC. However,
by afternoon it rose by 5ºC. What was the temperature recorded in the afternoon?

THINK SMART

1. Complete the following using the operations ‘+’, ‘–’, ‘×’ or ‘÷’.
(a) 7 4 2 = 9 (b) 8 6 3 = –1

(c) 25 5 9 = –4 (d) –18 2 8 = –8
2. Write two integers which are greater than –10 but their sum is less than –10.

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