year 8 maths

208 Chapter 4 Fractions, decimals, percentages and financial mathematics
Exercise 4B
REVISION
UNDERSTANDING AND FLUENCY
1–4, 5–11(½), 12–14 4, 5–11(½), 12–14
5–14(½)
The answers to questions 1 and 2 may be found in Key ideas.
1 a Which two operations require the denominators to be the same before proceeding?
b Which two operations do not require the denominators to be the same before proceeding?
2 a For which two operations must you first convert mixed numerals to improper fractions?
b For which two operations can you choose whether or not to convert mixed numerals to
improper fractions before proceeding?
3 State the LCD for the following pairs of fractions.
a
1
5 + 3 4
b
2
9 + 5 3
4 Rewrite the following examples and fill in the empty boxes.
a 2
3 + 1 4
b 7
8 − 9 16
c
11
25 + 7 10
c 1 4 7 × 3 5
d
5
12 + 13 8
d 5
7 ÷ 2 3
= 8 12 + □ 12
= □ 16 − 9 16
= □ 7 × 3 5
= 5 7 □ 3 2
= 11
□
= □ 16
= □ 35
= 15
□ = □ □ 14
Example 3
5 Evaluate:
1
a
5 + 2 5
b
7
9 − 2 9
c
5
8 + 7 8
d
24
7 − 11 7
e
3
4 + 2 5
f
3
10 + 4 5
g
5
7 − 2 3
h
11
18 − 1 6
Example 4
6 Evaluate:
a 3 1 7 + 1 3 7
b 7 2 5 + 2 1 5
c 3 5 8 − 1 2 8
d 8 5 11 − 7 3 11
e 5 1 3 + 4 1 6
f 17 5 7 + 4 1 2
g 6 1 2 − 2 3 4
h 4 2 5 − 2 5 6
Example 5a,b
7 Evaluate:
3
a
5 × 1 4
b
2
9 × 5 7
c
7
5 × 6 5
d
5
3 × 8 9
e
4
9 × 3 8
f
12
10 × 5 16
g
12
9 × 2 5
h
24
8 × 5 3
Example 5c
8 Evaluate:
a 2 3 4 × 1 1 3
b 3 2 7 × 1 3
c 4 1 6 × 3 3 5
d 10 1 2 × 3 1 3
9 State the reciprocal of the following fractions.
5
8
3
2
a
b
c 3 1 d 1 1 4
11
10 Write the first step for the following division questions. (There is no need to find the answer.)
3
a
13 ÷ 9 1
b
7
2 ÷ 1 17
c
4
10 ÷ 3 d 2 1 1
3 ÷ 1 3 4
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.