Flip Percentages for Easier Calculation

Problem

Some percentage calculations like "8% of 50" are harder to compute mentally than their flipped equivalent.

Solution

X% of Y = Y% of X. Always flip to whichever is easier. 8% of 50 = 50% of 8 = 4.

Benefit

Turns difficult percentage problems into trivial ones — works every time because multiplication is commutative.

Example

8% of 50 → hard
50% of 8 → easy = 4 ✓

4% of 75 → hard
75% of 4 → easy = 3 ✓

2% of 250 → hard
250% of 2 → easy = 5 ✓

15% of 40 → medium
40% of 15 → easy = 6 ✓

Why it works: (X/100) × Y = (Y/100) × X