50% is the change from 638 to 957
Calculation steps:
[( 957 - 638 ) ÷ 638] x 100 = 50%
Formula
Percentage change = [(957 - 638) / 638] x 100
Subtract the new number by the original number
957 - 638 = 319
319 ÷ 638 = 0.5
0.5 x 100 = 50%
Example