11+ Percentages
Percentages link fractions and decimals and appear constantly in 11+ word problems. A few core methods cover almost every question.
A percentage is simply a fraction out of 100, so 25% means 25/100 = 1/4 = 0.25. Being able to switch quickly between fractions, decimals and percentages saves time under pressure.
To find a percentage of an amount, the safest method is to find 10% first (divide by 10) and 1% (divide by 100), then build up the percentage you need. For example, 35% = 10% + 10% + 10% + 5%.
For percentage increase or decrease, find the percentage of the original amount and then add it on or take it away. Always read carefully whether the question asks for the change or the final value.
Worked examples
Q. Find 15% of £240.
10% of 240 = 24, and 5% is half of that = 12. So 15% = 24 + 12 = £36.
Q. A £80 coat is reduced by 25%. What is the sale price?
25% of 80 = 20. The reduction is £20, so the sale price is 80 − 20 = £60.
Common mistakes
- Giving the amount of change when the question asks for the final price (or vice versa).
- Confusing 1/2 a percent with 50%.
- Forgetting that a percentage increase is added to the original, not used on its own.
FAQs
What percentages should my child know by heart for the 11+?+
The fraction/decimal/percentage equivalents for 1/2, 1/4, 3/4, 1/5, 1/10 and 1/3 should be instant, as they appear in many questions.
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