Percentage Quarters: 25%, 50%, 75% Fast
Level 1 Mental percentages · Reviewed by The NumThink editorial team · Last reviewed
Short version: 25% = halve twice, 50% = halve once, 75% = three of those quarters: 75% of 320 → quarter = 80 → 3 × 80 = 240.
This page is part of the NumThink Mental percentages course. Read why the method works, watch it run on worked examples, then drill it in the practice box below until it feels automatic.
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No signup · instant feedbackWhy it works
50% is literally half, 25% a quarter, 75% three quarters — and halving is the most practiced mental operation there is.
Quarters and money think alike: 25% of $320 is exactly how you count quarters, which is why this method feels natural for prices.
The steps
- Halve once for 50%. 320 ÷ 2 = 160.
- Halve again for 25%. 160 ÷ 2 = 80.
- Scale for 75%. 75% = 25% × 3 → 80 × 3 = 240.
Worked examples
Easy 25% of 48
Show the thinking
48 ÷ 2 = 24
24 ÷ 2 = 12.
Answer: 12
Medium 75% of 320
Show the thinking
25% of 320 = 80
80 × 3 = 240.
Answer: 240
Hard 75% of 1,240
Show the thinking
25% of 1,240 = 310
310 × 3 = 930.
Answer: 930
When to use it
- Discounts (25% off, half price, 75% clearance), statistics, and tips.
- Any percentage that is a multiple of 25.
When NOT to use it
- Percentages like 15% or 30% — building blocks handle those better.
- Numbers that halve awkwardly twice (e.g. odd numbers with decimals) — check whether blocks are smoother.
Common mistakes
One halve only for 25%. Answering 160 for 25% of 320 (that is 50%). Fix: 25% = TWO halvings. 50% = one. Count them deliberately.
Using 25% as if it were 75%. Answering 80 for 75% of 320. Fix: After finding the quarter (80), ask: does my answer need one, two, or three of these?
Check yourself: 75% and 25% together make the whole: 240 + 80 = 320 ✓.