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Senior Phase Mathematics: Grade 7 – 9 Learner book

Questions

Unit 1.9: Integers

Grade 7, 8 and 9:

Calculate: b) 5 – 12 c) – 8 – 3 d) 23 – 46 e) 36 – 58
1a) 8 – 10

2a) – 5 – 2 b) – 7 + 3 c) – 8 + 10 d) – 12 – 15 e) – 32 + 14

3a) 6 – (–3) b) 8 + (–12) c) 12 – (–2) d) 26 + (–14) e) 28 + (–32)

4a) 9 + (–3) b) 12 – (–4) c) 39 + (–4) d) 48 – (–3) e) –12 – (–15)

5a) 240 – (–45) b) –36 – 42 c) –124 + 235 d) –14 + (–27) e) 143 – 189

6a) 3 – 5 + 7 b) –5 – 2 + 7 c) –23 + 27 – (–4) d) 2 + (–10) – 24

7. You may only use the following numbers to answer the questions:

–7; –5; –2; 2; 5; 7. ☐+☐=
a) Use two of the numbers to make the largest possible result.

b) Use two of the numbers to make the smallest possible result. ☐+☐=

c) Use two of the numbers to make the largest possible result. ☐–☐=

d) Use two of the numbers to make the smallest possible result. ☐–☐=

8. The temperature in Johannesburg was 7° C at 6 pm in the evening. By 6 am the next morning,
it had dropped by 9° C. By noon it had risen by 18° C. How many degrees warmer was it at
noon than at 6 pm the day before?

9. Clifford claims that adding two numbers will always give him a bigger answer than if he
subtracts two numbers. Is he correct? Explain why you say so.

Grade 8 and 9:

Calculate: b) –7 × 5 c) (–5) × (–8) d) 7 × (–2) e) (–8) × (–6)
10a) 6 × (–3) b) d)
–24 ÷ 6 c) (–49) ÷ (–7) 28 ÷ 7 e) –32 ÷ (–4)
11a) 18 ÷ (–3)
b) 24 ÷ (5–8) + 3 × (–2) c) (23– (–4)) ÷ 9 – 6
12a) 8 + 3(5 – 7)
13a) ିଵଶ × ଺ b) ିଵହ + 3(7 − 9) c) ଽା଺ − ଵ
ି଺ ଶ
ଽସ ିହ c)
−3ଶ − (−3)ଶ
14a) (−3)ଶ b) −3ଶ

15. Put a number in the box to make the following statements true:

a) ☐ + (–3) = 12 b) 15 + ☐ = 6 c) 15 – ☐ = 6

d) ☐– (–7) = –1 e) ☐– (–5) = 9 f) 235 + ☐ = 189

g) ☐– (–72) = –64 h) 145 – ☐ = 136 i) ☐ + (–13) = 22

j) ☐× (–5) = 15 k) 2 × ☐ = 10 l) 7 × ☐ = 21
m) ☐× 4 = –12 n) –120 ÷ ☐ = 20 p) ☐× (–12) = 84

16. Given ‫ = ݌‬−2, ‫ = ݍ‬7 and ‫ = ݎ‬−1.

Substitute these values into the expressions and simplify without using a calculator.

a) 2‫ݍ݌‬ b) (‫)݌ – ݍ‬ c) (‫ ݌‬+ ‫ ݌ – )ݍ‬
e) 10‫ݎ‬ଶ ÷ ‫݌‬ f) ‫ݍ‬ଶ − ‫ݍ݌‬
d) (‫ ݍ – )ݍ – ݌‬ h) 3‫ ݌‬+ 2‫ݍ‬ i) (‫ ݎݍ݌‬− ‫݌‬ଶ‫ݍ‬ଷ‫ݎ‬ସ)଴

g) 1
‫ ݍ݌‬− ‫ݎ‬
2

17. Two numbers have a sum of –6 and a product of –16. What are the two numbers?

18. Two numbers have a sum of –17 and a product of 72. What are the two numbers?

19. Two numbers have a quotient of 3 and a product of 12. Give all possible values for the two

numbers.

Winning Teams & Olico 28