This deep dive covers Method: Percentage Increase/Decrease 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 6 of 16 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Method: Percentage Increase/Decrease
1
Increase: Multiply by (100 + %)÷100
20% increase: × 1.2
2
Decrease: Multiply by (100 - %)÷100
15% decrease: × 0.85
3
Multiplier method: One-step calculation
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