1.4 Using percentages Learning objectives • To revise the links within fractions, decimals and percentages • To choose the correct calculation to work out a percentage These examples show the link between fractions and decimals. 1 = 1 ÷ 2 = 0.5 2 1 = 1 ÷ 4 = 0.25 4 1 = 1 ÷ 5 = 0.2 5 1 = 1 ÷ 8 = 0.125 8 1 = 1 ÷ 10 = 0.1 10
3 = 3 ÷ 4 = 0.75 4 2 = 2 ÷ 5 = 0.4 5 3 = 3 ÷ 8 = 0.375 8 3 = 3 ÷ 10 = 0.3 10
3 = 3 ÷ 5 = 0.6 5 5 = 5 ÷ 8 = 0.625 8 7 = 7 ÷ 10 = 0.7 10
4 = 4 ÷ 5 = 0.8 5 7 = 7 ÷ 8 = 0.875 8 9 = 9 ÷ 10 = 0.9 10
You can change a fraction to a decimal by dividing the numerator (top number) by the denominator (bottom number).
These examples show the link between decimals and percentages. 0.5 = 0.5 × 100% = 50% 0.25 = 0.25 × 100% = 25%
0.75 = 0.75 × 100% = 75%
0.2 = 0.2 × 100% = 20%
0.6 = 0.6 × 100% = 60%
0.4 = 0.4 × 100% = 40%
0.125 = 0.125 × 100% = 12.5%
0.375 = 0.375 × 100% = 37.5%
You can change a decimal to a percentage by multiplying the decimal by 100.
These examples show the link between fractions and percentages. 1 = 1 ÷ 2 × 100 = 0.5 × 100 = 50% 2 1 = 1 ÷ 4 × 100 = 0.25 × 100 = 25% 4 1 = 1 ÷ 5 × 100 = 0.2 × 100 = 20% 5 1 = 1 ÷ 8 × 100 = 0.125 × 100 = 12.5% 8 1 = 1 ÷ 10 × 100 = 0.1 × 100 = 10% 10
3 = 3 ÷ 4 × 100 = 0.75 × 100 = 75% 4 2 = 2 ÷ 5 × 100 = 0.4 × 100 = 40% 5 3 = 3 ÷ 8 × 100 = 0.375 × 100 = 37.5% 8 3 = 3 ÷ 10 × 100 = 0.3 × 100 = 30% 10
You can change a fraction to a percentage by dividing the numerator (top number) by the denominator (bottom number), then multiplying the decimal by 100.
1.4 Using percentages
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