KS2 SATs 2024 — Mathematics Paper 1: Arithmetic

The idea

Per cent means out of 100, so a percentage of an amount is a fraction of that amount. The fastest building block is 10%: divide the amount by 10. From there, 5% is half of 10%, and you can build many other percentages by adding blocks together.

For example, 35% is 10% + 10% + 10% + 5%. Some percentages have shortcuts: 50% is half the amount, 25% is a quarter, and 75% is 50% plus 25%. Choosing the easiest blocks keeps the working short.

Money amounts work the same way, but keep the units clear: work in pounds or in pence all the way through, and write the £ sign in your final answer when the question is about money.

Worked example

Work out 35% of £240.

1. Find 10% of £240: 240 ÷ 10 = £24.
2. So 30% is 3 × £24 = £72.
3. Find 5%, which is half of 10%: £24 ÷ 2 = £12.
4. Add the blocks: £72 + £12 = £84.

Answer: £84

Watch out

• Finding 10% by dividing by 100 instead of by 10.
• Stopping at the discount or percentage and forgetting what the question asked for.