-58.13% is the change from 640 to 268
Calculation steps:
[( 268 - 640 ) ÷ 640] x 100 = -58.13%
Formula
Percentage change = [(268 - 640) / 640] x 100
Subtract the new number by the original number
268 - 640 = -372
-372 ÷ 640 = -0.58125
-0.58125 x 100 = -58.13%