29.06% is the change from 640 to 826
Calculation steps:
[( 826 - 640 ) ÷ 640] x 100 = 29.06%
Formula
Percentage change = [(826 - 640) / 640] x 100
Subtract the new number by the original number
826 - 640 = 186
186 ÷ 640 = 0.290625
0.290625 x 100 = 29.06%