Page 78 - Cambridge Checkpoint Mathematics Coursebook 7_Slide 02

7.2 Recognising equivalent fractions, decimals and percentages

Percentages can be written as fractions with a denominator of 100, as the
14
words ‘per cent’ mean ‘out of 100’. 8% = 100 , 14% = 100
8
You need to be able to recognise equivalent fractions, decimals and
percentages.
Th e diagram shows the ones that are most commonly used.

Learn these and it will help you answer all sorts of questions in the future!

0.25 0.5 0.75
0 0.1 0.2 0.3 0.4 0.6 0.7 0.8 0.9 1

1 1 1 3 2 1 3 7 3 4 9
0 1
10 5 4 10 5 2 5 10 4 5 10

0 10% 20% 30% 40% 60% 70% 80% 90% 100%
25% 50% 75%

Worked example 7.2B

a Write the following percentages as fractions. i 5% ii 83%
b Write 20% as: i a fraction ii a decimal.

5
a i 5% = 100 5 per cent means 5 out of 100.
5 1 5
100 = 20 100 can be cancelled by dividing 5 and 100 by 5.

83 83
ii 83% = 100 83 per cent means 83 out of 100 100 cannot be cancelled.

1
20
B i 20% = 1 20% is a commonly used percentage, 20% as a fraction is 100 = .
5
5
ii 20% = 0.2 20% as a decimal is 0.2.
✦ Exercise 7.2

1 Write these decimal numbers as fractions in their simplest form.
a 0.3 b 0.9 c 0.2 d 0.6 e 0.8
f 0.17 g 0.35 h 0.84 i 0.07 j 0.04
k 0.139 l 0.125 m 0.826 n 0.042 o 0.006

2 Write these percentages as fractions.
a 9% b 27% c 81% d 69% e 11%

76 7 Fractions