year 8 maths

220 Chapter 4 Fractions, decimals, percentages and financial mathematics
Example 13
Dividing decimals
Calculate:
a 35.756 ÷ 4 b 64.137 ÷ 0.03
SOLUTION
a 8.939
8. 9 3 9
4⟌35. 3 7 1 5 3 6
b 64.137 ÷ 0.03
= 6413.7 ÷ 3 = 2137.9
2 1 3 7. 9
3⟌64 1 1 2 3. 2 7
EXPLANATION
Carry out division, remembering that the decimal point
in the answer is placed directly above the decimal point
in the dividend.
Instead of dividing by 0.03 , multiply both the divisor
and the dividend by 100.
Move each decimal point two places to the right.
Carry out the division question 6413.7 ÷ 3 .
Exercise 4D
REVISION
UNDERSTANDING AND FLUENCY
1, 2–4(½), 5, 6(½), 7, 8(½), 9, 10–11(½) 2–4(½), 5, 6(½), 7, 8(½), 9, 10–11(½) 5, 6(½), 7, 8(½), 9, 10–12(½)
1 Which of the following is correctly set up for the following addition?
5.386 + 53.86 + 538.6
Example 10
A 5.386
53.86
+ 538.6
B 5.386
53.860
+ 538.600
C 5.386
53.86
+ 538.6
D 538 + 53 + 5
+ 0.386 + 0.86 + 0.6
2 Calculate:
a 23.57 + 39.14 b 64.28 + 213.71 c 5.623 + 18.34 d 92.3 + 1.872
e 38.52 − 24.11 f 76.74 − 53.62 g 123.8 − 39.21 h 14.57 − 9.8
3 Calculate:
a 13.546 + 35.2 + 9.27 + 121.7 b 45.983 + 3.41 + 0.032 + 0.8942
c 923.8 + 92.38 + 9.238 + 0.238 d 4.572 + 0.0329 + 2.0035 + 11.7003
4 Calculate:
a 3.456 + 12.723 − 4.59 b 7.213 − 5.46 + 8.031
c 26.451 + 8.364 − 14.987 d 12.7 − 3.45 − 4.67
Example 11
Example 12
5 The correct answer to the problem 2.731 ÷ 1000 is:
A 2731 B 27.31 C 2.731 D 0.02731 E 0.002731
6 Calculate:
a 36.5173 × 100 b 0.08155 × 1000 c 7.5 ÷ 10 d 3.812 ÷ 100
e 634.8 × 10 000 f 1.0615 ÷ 1000 g 0.003 × 10 000 h 0.452 ÷ 1000
7 If 56 × 37 = 2072 , the correct answer to the problem 5.6 × 3.7 is:
A 207.2 B 2072 C 20.72 D 2.072 E 0.2072
8 Calculate:
a 12.45 × 8 b 4.135 × 3 c 26.2 × 4.1 d 5.71 × 0.32
e 0.0023 × 8.1 f 300.4 × 2.2 g 7.123 × 12.5 h 81.4 × 3.59
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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