Maths · Fractions
Fractions of numbers
Find fractions of quantities, like 3/4 of 20.
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What does 'fraction of' mean?
When we find a fraction of a number, we share it into equal parts. Then we take some of those parts. For example, half of 10 means we split 10 into 2 equal parts. Each part is 5, so half of 10 is 5.
Finding a fraction of a number
To find a fraction of a number, we divide by the bottom number. Then we multiply by the top number. The bottom number tells us how many equal parts to make. The top number tells us how many parts to take.
A quick method
Let's find one third of 12. First, divide 12 by 3 to get 4. That's one third. If we wanted two thirds, we'd multiply 4 by 2 to get 8. So two thirds of 12 is 8.
Why does this work?
Imagine 12 sweets shared equally among 3 friends. Each friend gets 4 sweets. That's one third of 12. If two friends put their sweets together, they have 8. That's two thirds of 12.
Worked examples
1. Find 3/4 of 20
- First, divide 20 by 4 to find one quarter: 20 ÷ 4 = 5
- One quarter of 20 is 5.
- Now multiply by 3 to find three quarters: 5 × 3 = 15
- So 3/4 of 20 is 15.
2. Find 2/5 of 30
- First, divide 30 by 5 to find one fifth: 30 ÷ 5 = 6
- One fifth of 30 is 6.
- Now multiply by 2 to find two fifths: 6 × 2 = 12
- So 2/5 of 30 is 12.
3. Find 5/6 of 18
- First, divide 18 by 6 to find one sixth: 18 ÷ 6 = 3
- One sixth of 18 is 3.
- Now multiply by 5 to find five sixths: 3 × 5 = 15
- So 5/6 of 18 is 15.
Try it yourself
Find 3/5 of 25
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