year 8 maths

4C
Decimal place value and fraction/decimal conversions
213
Example 8
Converting decimals to fractions
Convert the following decimals to fractions in their simplest form.
a 0.725 b 5.12
SOLUTION
a
725
1000 = 29
40
b 5 12
100 = 5 3 25
EXPLANATION
Three decimal places, therefore three zeros in
denominator.
0.725 = 725 thousandths
Two decimal places, therefore two zeros in
denominator.
0.12 = 12 hundredths
Example 9
Converting fractions to decimals
Convert the following fractions to decimals.
239
a
100
b
9
25
SOLUTION
EXPLANATION
239
a
100 = 2 39
100 = 2.39 Convert improper fraction to a mixed numeral.
Denominator is a power of 10 .
9
b
25 = 36
100 = 0.36 9
25 = 9 × 4
25 × 4 = 36
100
Exercise 4C
REVISION
UNDERSTANDING AND FLUENCY
1–6, 7(½), 8 4, 5(½), 6, 7–8(½), 9 5(½), 7–8(½), 9
Example 7
1 Compare the following decimals and place the correct inequality sign (< or >) between them.
a 36.485 37.123
b 21.953 21.864
c 0.0372 0.0375
d 4.21753 4.21809
e 65.4112 64.8774
f 9.5281352 9.5281347
2 Arrange the following sets of decimals in descending order.
a 3.625, 3.256, 2.653, 3.229, 2.814, 3.6521
b 11.907, 11.891, 11.875, 11.908, 11.898, 11.799
c 0.043, 1.305, 0.802, 0.765, 0.039, 1.326
3 Which of the following is the mixed numeral equivalent of 8.17 ?
1
17
1
17
A 8
B 8
C 8
D 8
7
10
17
1000
17
E 8
100
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
Photocopying is restricted under law and this material must not be transferred to another party.