31.25% is the change from 64 to 84
Calculation steps:
[( 84 - 64 ) ÷ 64] x 100 = 31.25%
Formula
Percentage change = [(84 - 64) / 64] x 100
Subtract the new number by the original number
84 - 64 = 20
20 ÷ 64 = 0.3125
0.3125 x 100 = 31.25%
Example