Step-by-Step Process
- Identify the percentage decrease
- Convert to decimal: percentage ÷ 100
- Subtract from 1: 1 - decimal = multiplier
- Multiply original by multiplier
Why Subtract from 1?
When we decrease by 25%, we want:
- Original amount (100%) - Removed amount (25%) = 75%
- 75% = 0.75 as a decimal
- So multiplier = 1 - 0.25 = 0.75
Common Multipliers
| Decrease | Multiplier | Calculation |
|---|---|---|
| 5% | 0.95 | 1 - 0.05 |
| 10% | 0.90 | 1 - 0.10 |
| 15% | 0.85 | 1 - 0.15 |
| 20% | 0.80 | 1 - 0.20 |
| 25% | 0.75 | 1 - 0.25 |
| 30% | 0.70 | 1 - 0.30 |
This deep dive covers The Multiplier Method Explained within Percentage Decrease for GCSE Mathematics. Revise Percentage Decrease in Ratio & Proportion for GCSE Mathematics with 12 exam-style questions and 22 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 3 of 6 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Percentage Decrease
What multiplier is used to decrease a value by 35%?
A shop advertises '25% off everything'. A student says: 'The multiplier is 0.25 because 25% = 0.25.' Explain what is wrong with the student's reasoning and state the correct multiplier.
Quick recall flashcards
What is a percentage decrease?
Finding a new amount after subtracting a percentage from the original amount
What is the multiplier for a 10% decrease?
0.90 (because 1 - 0.10 = 0.90)