25% is the change from 320 to 400
Calculation steps:
[( 400 - 320 ) ÷ 320] x 100 = 25%
Formula
Percentage change = [(400 - 320) / 320] x 100
Subtract the new number by the original number
400 - 320 = 80
80 ÷ 320 = 0.25
0.25 x 100 = 25%
Example