-16.25% is the change from 640 to 536
Calculation steps:
[( 536 - 640 ) ÷ 640] x 100 = -16.25%
Formula
Percentage change = [(536 - 640) / 640] x 100
Subtract the new number by the original number
536 - 640 = -104
-104 ÷ 640 = -0.1625
-0.1625 x 100 = -16.25%