Percentages — Master the Per-Hundred
What % really means, fraction shortcuts, and the successive-change trick that saves time in every exam.
By the PadhoDost Team · 📖 6 min read · Updated 4 August 2026
Part of SSC CGL & Banking prep🧠 Percent = per hundred
The word 'percent' literally means 'per hundred'. So 25% just means 25 out of every 100, i.e. 25/100 = ¼. Once you see every percentage as a simple fraction, the maths becomes mental.
The one formula
Know these by heart
| Percent | Fraction | Quick use |
|---|---|---|
| 50% | 1/2 | half |
| 25% | 1/4 | quarter |
| 20% | 1/5 | ÷5 |
| 12.5% | 1/8 | ÷8 |
| 33⅓% | 1/3 | ÷3 |
The successive-change trick
When a value goes up by a% and then down by b%, don't subtract — multiply the factors. An increase of 20% then a decrease of 20% is 1.2 × 0.8 = 0.96, i.e. a net 4% DECREASE (not zero!).
📝 A salary rises 10%, then falls 10%. Net change?
Factor = 1.10 × 0.90 = 0.99
0.99 means 99% of the original → a 1% net decrease.
⚡ Quick check
40% of a number is 80. What is the number?
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