x% of y = y% of x
Swap the numbers in a percentage to make it easier.
x% of y = y% of x
1How it works
Because a percentage is just multiplication, x% of y always equals y% of x. Swapping often turns a hard calculation into an easy one.
2How to apply (in seconds)
- Write the expression as x% of y.
- Swap to y% of x if that is simpler.
- Compute the easier version.
3Worked examples
Example 1 Worked solution
Q. Find 16% of 25.
- 16% of 25 = 25% of 16.
- 25% of 16 = 16 ÷ 4.
✓ 4
4When to use it
- ✦Mental percentage calculations.
- ✦Data interpretation speed-ups.
5Cautions & tips
- !Look for a side that gives a clean fraction like 25% or 50%.