4070% is the change from 20 to 834
Calculation steps:
[( 834 - 20 ) ÷ 20] x 100 = 4070%
Formula
Percentage change = [(834 - 20) / 20] x 100
Subtract the new number by the original number
834 - 20 = 814
814 ÷ 20 = 40.7
40.7 x 100 = 4070%
Example