1990% is the change from 40 to 836
Calculation steps:
[( 836 - 40 ) ÷ 40] x 100 = 1990%
Formula
Percentage change = [(836 - 40) / 40] x 100
Subtract the new number by the original number
836 - 40 = 796
796 ÷ 40 = 19.9
19.9 x 100 = 1990%
Example