-48.91% is the change from 640 to 327
Calculation steps:
[( 327 - 640 ) ÷ 640] x 100 = -48.91%
Formula
Percentage change = [(327 - 640) / 640] x 100
Subtract the new number by the original number
327 - 640 = -313
-313 ÷ 640 = -0.4890625
-0.4890625 x 100 = -48.91%