-62.81% is the change from 640 to 238
Calculation steps:
[( 238 - 640 ) ÷ 640] x 100 = -62.81%
Formula
Percentage change = [(238 - 640) / 640] x 100
Subtract the new number by the original number
238 - 640 = -402
-402 ÷ 640 = -0.628125
-0.628125 x 100 = -62.81%