Per cent means 'out of 100', so a percentage is a share of an amount. To find 25% of 80, turn the percent into hundredths and multiply: 25 ÷ 100 × 80 = 20. A quick way is to find 1% first (divide by 100) and then multiply by the percent, or use friendly benchmarks — 10% is a tenth, 25% is a quarter, 50% is a half. The answer is always a part of the original amount, so it can never be bigger than what you started with.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- per cent
- out of 100 (the symbol is %)
- of
- in percentage questions this means multiply
- quantity
- the whole amount you take a share of
Worked examples
50% of 40
- 1.50% is one half.
- 2.40 ÷ 2 = 20.
= 20
25% of 80
- 1.25% is one quarter.
- 2.25 ÷ 100 × 80 = 20.
= 20
10% of 120
- 1.10% is one tenth.
- 2.120 ÷ 10 = 12.
= 12
For parents
Method: Benchmarks (10%, 25%, 50%) and dividing by 100 for 1%.
What to say: Ask 'twenty-five percent of WHAT?' so the percent is treated as a share, not the answer.
Common mistakes:
- Writing the percent as the answer (25% of 80 → 25).
- Forgetting to divide by 100 (25 × 80 → 2000).
- Subtracting the percent from the quantity (80 − 25 → 55).