Use the part-to-whole ratio as a cross-check
16:80 simplifies to 1:5. Reading that reduced ratio as a decimal and multiplying by 100 gives the same percentage, which is a useful check on the direct formula.
- 1.Form the ratio 16 ÷ 80.
- 2.16 ÷ 80 = 0.2.
- 3.0.2 × 100 = 20%.