CAMBRIDGE O LEVEL MATHEMATICS: COURSEBOOK ANSWERS

Exercise 1.6A 11 a 34 minutes

1 a 23 cm b 2000 seconds

b 23 g 12 a 250

c 306 kg b 65

d 91 m c 2.5

e 300 km d 8.25

f 400 e 1.435

g 30
h 10 100 Exercise 1.6B
1 a Correct
i 600
b Incorrect; 5560
j 3 901 000
c incorrect; 0.09
2 440 minutes
d Incorrect; 0.095
3 49 kg
2 a 470
4 42 000 m
b 1200
5 210 seconds
c 0.078
6 a 2.316
d 6.1
b 2.32
e 80 000
c 19.21
f 5
d 26.7
g 20
e 26.75
h 0.0003
f 0.147
i 5.84
g 12.1
j 84.3
h 21.09
k 1.00
i 13.01
l 100
j 40.000
3 a 6m
7 a 1000
b 610 cm
b 1200
4 a 15 700 mm
8 a 379 m
b 1573 cm
b 37 863 cm
c 20 m
9 a 6 kg
5 Henry has rounded an already-rounded
b 5.6 kg number
c 5.56 kg He should round 3649.7 to 2 significant
10 a 4506.6 cm 2 figures as 3600

b 4507 cm2 6 2600 g

6 Cambridge O Level Mathematics – Chalmers & Saya © Cambridge University Press 2023
 CAMBRIDGE O LEVEL MATHEMATICS: COURSEBOOK ANSWERS

7 a 2350 m3 Check your skills

b 1200 m 3 (Sections 1.7–1.8)
8 a 0.005 1 13

b 500 2 4277

c 0.002 3 0.693

d 0.004
Exercise 1.7A
Exercise 1.6C 1 a 1
3
1 a 7 1
b
b 5 25
1
c 6 c 16
d 2 2
d 3
e 11 e 8
f 9 2 a 243

2 a 50 × 8 gives 40 b 64
10
100 gives 25 c 125
b
3 +1
d 49
c 90 − 40 gives 2
e 1
52
25
d 43 gives 4 f 256
8×2
33 + 30 gives 3 g 729
e
20 − 1
3 a 8
100 − 22
f gives 60 1
0.1 b
9
3
1000 c 32
g gives 50
0.1 + 0.1
3 × (9 − 4 )2 d 81
h gives 5
20 − 5
e 25
3 a 1400 m
f 1
b 2 significant figures / nearest hundred 1
g
7
c Estimate of 1460 m is closer to the actual
distance, but is now correct to only 1 4 a 4
significant figure (nearest thousand) b 27
4 a 50 ºC 1
c
25
b $100 000 1
d
2
5 a i 2 decimal places or 5 significant
figures
ii 660 cm2
Exercise 1.7B
1 a 144
b 10 cm up to 15 cm
b 10 000

7 Cambridge O Level Mathematics – Chalmers & Saya © Cambridge University Press 2023