Foundation and Higher · fractions and percentages of amounts
Fractions and
percentages
of an amount.
“of” means multiply
in maths, one small word —
of
35 of 40 means 35 × 40
35% of 80 means 0.35 × 80
step 1 of 4
Fraction of an amount
1. Divide by the bottom: one part is 8.
2. Multiply by the top: three parts are 24.
✓ Divide by the bottom, times by the top
35 of 40
step 2 of 4
Percentage: build it up
1. Find 10% first: divide by 10.
2. 30% is three of those. 5% is half.
✓ No calculator needed
35% of 80
10% = 8 ÷ 10
30% = 245% = 4
35% = 24 + 4 = 28
step 3 of 4
Percentage: multiplier
1. Percent means out of 100: divide by 100.
2. Multiply the amount by that decimal.
✓ The calculator method
35% of 80
35% = 35100 = 0.35
0.35 × 80 = 28
step 4 of 4
As a percentage
1. Write it as a fraction: 18 over 24.
2. Turn it into a decimal, then × 100.
✓ 18 out of 24 is 75%
18 out of 24
= 1824 = 34
= 0.75
= 75%
of an amount —
Fraction of
÷ bottom, × top
Percentage of
build from 10%, or use a multiplier
As a percentage
fraction, decimal, × 100
1% is ÷ 100. 5% is half of 10%.
Everything builds from those.
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