-9.77% is the change from 256 to 231
Calculation steps:
[( 231 - 256 ) ÷ 256] x 100 = -9.77%
Formula
Percentage change = [(231 - 256) / 256] x 100
Subtract the new number by the original number
231 - 256 = -25
-25 ÷ 256 = -0.09765625
-0.09765625 x 100 = -9.77%