49.38% is the change from 640 to 956
Calculation steps:
[( 956 - 640 ) ÷ 640] x 100 = 49.38%
Formula
Percentage change = [(956 - 640) / 640] x 100
Subtract the new number by the original number
956 - 640 = 316
316 ÷ 640 = 0.49375
0.49375 x 100 = 49.38%