-36.88% is the change from 640 to 404
Calculation steps:
[( 404 - 640 ) ÷ 640] x 100 = -36.88%
Formula
Percentage change = [(404 - 640) / 640] x 100
Subtract the new number by the original number
404 - 640 = -236
-236 ÷ 640 = -0.36875
-0.36875 x 100 = -36.88%