75% is the change from 12 to 21
Calculation steps:
[( 21 - 12 ) ÷ 12] x 100 = 75%
Formula
Percentage change = [(21 - 12) / 12] x 100
Subtract the new number by the original number
21 - 12 = 9
9 ÷ 12 = 0.75
0.75 x 100 = 75%
Example