Key Concepts in Percentages
- Finding percentages of amounts
- Percentage increase and decrease
- Reverse percentages
- Compound interest
- Percentage change
Exam Tips for Percentages
- 💡Use multipliers for percentage change (e.g. 20% increase → × 1.2)
- 💡For reverse percentages, divide by the multiplier
- 💡Compound interest formula: A = P(1 + r/100)ⁿ
Exam Board Coverage
Percentages appears on all major GCSE Maths exam boards at both Foundation and Higher tier.
AQA
Edexcel
OCR
Frequently Asked Questions
What is a multiplier in percentage calculations?
A multiplier is the decimal you multiply by to apply a percentage change. A 20% increase uses multiplier 1.2; a 15% decrease uses multiplier 0.85.
How do I work out a reverse percentage?
If you know a value after a percentage change, divide by the multiplier. E.g. after a 25% increase gives £75, the original was 75 ÷ 1.25 = £60.
What is compound interest?
Compound interest means interest is calculated on both the original amount and the accumulated interest. Use A = P(1 + r/100)ⁿ where P is principal, r is rate, n is number of years.