Percentage Revision Card
Free printable revision card designed to fit on A5 paper or fold to wallet size.
Percentage Revision Card
percentages.co.uk
Key Formulas
| Formula | Expression |
|---|---|
| % of a number | (P ÷ 100) × N |
| % increase | Original × (1 + P/100) |
| % decrease | Original × (1 - P/100) |
| Reverse % | Amount ÷ (1 ± P/100) |
| % change | ((New - Old) ÷ Old) × 100 |
| % difference | (|A - B| ÷ Avg) × 100 |
Common Equivalents
50% = 0.5 = 1/2
25% = 0.25 = 1/4
75% = 0.75 = 3/4
10% = 0.1 = 1/10
20% = 0.2 = 1/5
5% = 0.05 = 1/20
1% = 0.01 = 1/100
100% = 1
Worked Examples
What is 15% of £240?
0.15 × 240 = £36
A jacket falls from £80 to £60. Percentage decrease?
(20 ÷ 80) × 100 = 25%
After a 20% rise, a price is £180. Original?
180 ÷ 1.2 = £150
Mental Maths Shortcuts
10%:divide by 10
5%:halve the 10% value
1%:divide by 100
50%:halve the number
25%:halve, then halve again
20%:double the 10% value
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