5% is the change from 20 to 21
Calculation steps:
[( 21 - 20 ) ÷ 20] x 100 = 5%
Formula
Percentage change = [(21 - 20) / 20] x 100
Subtract the new number by the original number
21 - 20 = 1
1 ÷ 20 = 0.05
0.05 x 100 = 5%
Example