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LEVEL 7
Percentage Speed Tricks
Reversal Trick
118% of 50 is hard.
2Flip it: 50% of 18 = 18 ÷ 2 = 9.
3Rule: x% of y = y% of x (always!)
4Use this when one % is a benchmark (10, 25, 50, 75)
10% Breakdown
117% of 80 is hard.
210% of 80 = 8 (just move decimal)
37% of 80 = 7 × 0.8 = 5.6
4Answer: 8 + 5.6 = 13.6
Benchmark Method
125% = ÷ 4
250% = ÷ 2
375% = ÷ 4 × 3
420% = ÷ 5
533⅓% ≈ ÷ 3
Percentage of 100
1x% of 100 = x (always!)
217% of 100 = 17
3234% of 100 = 234
4Scale up: 17% of 200 = 17 × 2 = 34
Quick Reference
10%÷ 10
20%÷ 5
25%÷ 4
33⅓%÷ 3
50%÷ 2
75%÷ 4 × 3
1%÷ 100
200%× 2