This deep dive covers Higher Level: Compound Percentages within Percentages for GCSE Mathematics. Revise Percentages in Number for GCSE Mathematics with 14 exam-style questions and 22 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 12 of 16 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Higher Level: Compound Percentages
Multiple percentage changes:
- NOT additive: 10% increase then 10% decrease ≠ 0% change
- Multiply multipliers: +10% then -10% = 1.1 × 0.9 = 0.99 = -1%
- Order doesn't matter: +20% then +30% = ×1.2 ×1.3 = ×1.56 = +56%
Example: Price increases 20%, then decreases 15%
Overall multiplier = 1.2 × 0.85 = 1.02 = +2% overall
Practice questions for Percentages
Which calculation correctly finds 35% of £240 using the decimal method?
Which formula correctly expresses one quantity as a percentage of another?
Quick recall flashcards
Percentage to decimal
Divide by 100
75% = 0.75
8% = 0.08
150% = 1.5
Move decimal point 2 places left
What is a percentage?
Parts per hundred
Percent = per cent = per 100
% symbol means 'out of 100'
50% = 50/100 = half