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Practice Time 1B

1. Multiply the following.
(a) 7 by 11 (b) (–12) by 11 (c) 9 by (–1) (d) (–4) by (–107)
2. Find the product.

(a) 16 × 8 (b) (–13) × 17 (c) 19 × (–21) (d) (–10) × (– 98)
(e) (15) × (–22) × (–5) × (–8) (f) (–4) × (–5) × (–6) × (–1)
3. Find the product.

(a) (–1) × (–1) × (–1) × (–1) (b) (–1) × (–1) × (–1) × (–1) × (–1) × (–1)
(c) (–1) × (–1) × (–1) × … (149 times) (d) (–1) × (–1) × (–1) × … (240 times)
4. Fill in the blanks.

(a) (–7) × .......... = 0 (b) 8 × .......... = –8
(c) .......... × 1 = –23 (d) .......... × 1 = (–11)
(e) (–5) × (103 – 3) = (–5) × .......... – (–5) × 3 (f) (–1) × [(–2) + 3] = (–1) × .......... + (–1) × 3

5. Evaluate the following using suitable property.
(a) (–25) × 203 (b) (–11) × (–12) × (–13)
(c) (–4) × [7+ (–6)] (d) (–12) × (–99) + (–12) × (–1)
(e) (–4) × [(–100) –9] (f) 1927 × 101 – 1927 × (–9)

6. Verify the following.
(a) x × (y + z) = (x × y) + (x × z), if x = –2, y = –1, and z = 3.

(b) x × (y × z) = (x × y ) × z, if x = –2, and y = –1
7. What will be the sign of the product, if
(a) 17 –ve integers are multiplied with 3 +ve integers?
(b) 28 –ve integers are multiplied with 4 +ve integers?

(c) 7 +ve integers are multiplied with 2 –ve integers?
(d) 27 –ve integers are multiplied together?

1
8. For any non-zero integer x, what is the value of (–1) × x + x × 0 + x × at x = 1?
x
9. A bakery earns a profit of `10 per loaf of bread sold and incurs a loss of `7 per cake sold. The bakery
sells 2500 loaves of bread and 4000 cakes in a month. What is its profit or loss?

10. A cooling process requires that the room temperatures be lowered from 35°C at a variable rate. For
the first 3 hours, the temperature decreases by 4°C per hour. For the next 4 hours, the temperature
decreases by 3°C per hour. What will be the room temperature 10 hours after the process begins?
What is general room temperature in degree celsius and degree Fahrenheit?

Life Skills

A submarine is diving from the sea surface at the rate of 63 feet per minute. What will be the depth of the
submarine after 8 minutes? At what possible depth in the sea a person can dive safely?

17 Integers