6
a Work out 2.3 × 7.5. b Use your answer to part a and the fact that 4.1 × 7.5 = 30.75, to work out 6.4 × 7.5.
7
Evaluate each of these. a 3.12 × 14
8
b 5.24 × 15
c 1.36 × 22
d 7.53 × 25
e 27.1 × 32
Work out the total cost of each purchase. a Twenty-four litres of petrol at £0.92 per litre b Eighteen pints of milk at £0.32 per pint c Fourteen magazines at £2.25 per copy
9
A CD case is 0.8 cm thick. How many cases are in a pile of CDs that is 16 cm high?
10
a Use any method to work out 64 ÷ 4. b Use your answer to part a to work out each of these. i 6.4 ÷ 0.04
11
ii 0.64 ÷ 4
iii 0.064 ÷ 0.4
Here are three calculations. 43.68 ÷ 5.6
21.7 ÷ 6.2
19.74 ÷ 2.1
Which has the largest answer? Show how you know.
1.3 Approximation of calculations Homework 1C 1
2
3
4
Round each number to 1 significant figure. a 51 203
b 56 189
c 33 261
d 89 998
e 94 999
f 53.71
g 87.24
h 31.06
i 97.835
j 184.23
k 0.5124
l 0.2765
m 0.006 12
n 0.049 21
o 0.000 888
p 9.7
q 85.1
r 91.86
s 196
t 987.65
What are the least and the greatest numbers of people that live in these towns? a Hellaby
population 900 (to 1 significant figure)
b Hook
population 650 (to 2 significant figure)
c Hundleton
population 1050 (to 3 significant figures)
Round each number to 2 significant figures. a 6725
b 35 724
c 68 522
d 41 689
e 27 308
f 6973
g 2174
h 958
i 439
j 327.6
Round each number to the number of significant figures (sf) indicated. a 46 302 (1 sf)
b 6177 (2 sf)
c 89.67 (3 sf)
d 216.7 (2 sf)
e 7.78 (1 sf)
f 1.087 (2 sf)
g 729.9 (3 sf)
h 5821 (1 sf)
i 66.51 (2 sf)
j 5.986 (1 sf)
k 7.552 (1 sf)
l 9.7454 (3 sf)
m 25.76 (2 sf)
n 28.53 (1 sf)
o 869.89 (3 sf)
p 35.88 (1 sf)
q 0.084 71 (2 sf)
r 0.0099 (2 sf)
s 0.0809 (1 sf)
t 0.061 97 (3 sf)
1.3 Approximation of calculations
13834_P005_012.indd 7
7
1/7/15 12:07 PM