-24.22% is the change from 640 to 485
Calculation steps:
[( 485 - 640 ) ÷ 640] x 100 = -24.22%
Formula
Percentage change = [(485 - 640) / 640] x 100
Subtract the new number by the original number
485 - 640 = -155
-155 ÷ 640 = -0.2421875
-0.2421875 x 100 = -24.22%