-17.66% is the change from 640 to 527
Calculation steps:
[( 527 - 640 ) ÷ 640] x 100 = -17.66%
Formula
Percentage change = [(527 - 640) / 640] x 100
Subtract the new number by the original number
527 - 640 = -113
-113 ÷ 640 = -0.1765625
-0.1765625 x 100 = -17.66%