Page 26 - Start Up Mathematics_7

4. Associative property is valid for division of integers.

5. When two negative integers are divided the sign of the resulting quotient is positive.
6. If a, b, c are integers, then a ÷ (b + c) = (a ÷ b) + (a ÷ c).
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7. If a and b are integers, then (a – b) = (b – a) .
Fill in the Blanks

1. Sign of the product of two integers that are opposite in sign is ___________.
2. Additive inverse of an integer a is ______.
3. The value of the expression (–3) × (–1) × (–2) is ______.

4. There are __________ pairs of integers satisfying a ÷ b = –2.
5. The distance of any integer from zero is equal to its _____________.

Use the correct symbol >, < or = in questions numbered 6 and 7.
6. (–10) + (50) 30 + (–100)

7. (–18) × 0 × 7 (–12) × (–5)

In questions numbered 8 and 9 write an integer in the box to make them true.
8. × (4 + 9) = 7 × 4 + 7 × 9
9. (–7) × 4 + (–7) × = –7 × (4 + 2)

Answer in One Word or a Line
1. Which two integers have modulus value 3?

2. Name the identity element of integers with respect to addition.
3. If even number of negative integers are multiplied, what will be the sign of the product?
4. If odd number of negative integers are multiplied, what will be the sign of the product?

5. What will be the sign of product of 3 negative and 3 positive integers?
6. What is the product of any integer with 0?

let’s evaluate
1. Find the products in each case:

(a) (–16) × (–4) × (–3) (b) (–10) × (4) × 0 × (–36) (c) (–12) × (–5) × (–2) × (–10)
2. Simplify using suitable properties:
(a) 12 × (–3) + 5 × (–3) (b) (–10) × (–7) + (–10) × (–3)

3. 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?
4. A cement company earns a profit of ` 18 per bag of white cement sold and a loss of ` 5 per
bag of grey cement sold.

(a) The company sells 2,000 bags of white cement and 3,000 bags of grey cement in a month.
What is its profit or loss?
(b) If the company sells 3,600 grey bags, find the number of white cement bags it must sell
to make no profit no loss.

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