A fraction, a decimal and a percentage can all describe the same amount. To write a fraction as a percentage, multiply by 100: 1/4 = 1 × 100 ÷ 4 = 25, so 1/4 = 25%. It helps to learn the common ones by heart — 1/2 = 50%, 1/4 = 25%, 3/4 = 75%, 1/5 = 20%, 1/10 = 10%. Both numbers in the fraction matter: the bottom number tells you how many equal parts, and the top number tells you how many of them you have.
Explore this idea with maths tools
Equal parts, equal wholes
2/4 = 4/8
Both bars are the same length. Find a division of the second bar that lines up exactly with the coloured edge.
Words to know
- numerator
- the top number of a fraction
- denominator
- the bottom number: how many equal parts
- equivalent
- different ways of writing the same value
Worked examples
1/2 as a %
- 1.1 × 100 ÷ 2 = 50.
- 2.So 1/2 = 50%.
= 50
1/4 as a %
- 1.1 × 100 ÷ 4 = 25.
- 2.So 1/4 = 25%.
= 25
3/5 as a %
- 1.3 × 100 ÷ 5 = 60.
- 2.So 3/5 = 60%.
= 60
For parents
Method: Convert to 'out of 100' by multiplying by 100.
What to say: Ask how many equal parts the whole is split into, so the denominator isn't ignored.
Common mistakes:
- Reading the two numbers as digits (1/4 → 14%).
- Giving just the numerator (1/4 → 1%).
- Giving the denominator as the percent (1/4 → 4%).