-54.06% is the change from 640 to 294
Calculation steps:
[( 294 - 640 ) ÷ 640] x 100 = -54.06%
Formula
Percentage change = [(294 - 640) / 640] x 100
Subtract the new number by the original number
294 - 640 = -346
-346 ÷ 640 = -0.540625
-0.540625 x 100 = -54.06%