-77.5% is the change from 640 to 144
Calculation steps:
[( 144 - 640 ) ÷ 640] x 100 = -77.5%
Formula
Percentage change = [(144 - 640) / 640] x 100
Subtract the new number by the original number
144 - 640 = -496
-496 ÷ 640 = -0.775
-0.775 x 100 = -77.5%