Flip the Percent
A% of B equals B% of A — pick whichever side is easier.
8% of 50 = 4
8% of 50 is 8 × 50 ÷ 100. Swap the factors and it reads 50% of 8.
50% of 8 is half of 8: 4. When the percent is ugly and the number friendly, flip.
Your turn
Three to try in your head — tap what you get.
20% of 50
10% of 50
6% of 50
All 36 shortcuts: the Magic Tricks library.