-27.97% is the change from 640 to 461
Calculation steps:
[( 461 - 640 ) ÷ 640] x 100 = -27.97%
Formula
Percentage change = [(461 - 640) / 640] x 100
Subtract the new number by the original number
461 - 640 = -179
-179 ÷ 640 = -0.2796875
-0.2796875 x 100 = -27.97%