-25% is the change from 256 to 192
Calculation steps:
[( 192 - 256 ) ÷ 256] x 100 = -25%
Formula
Percentage change = [(192 - 256) / 256] x 100
Subtract the new number by the original number
192 - 256 = -64
-64 ÷ 256 = -0.25
-0.25 x 100 = -25%
Example