4150% is the change from 20 to 850
Calculation steps:
[( 850 - 20 ) ÷ 20] x 100 = 4150%
Formula
Percentage change = [(850 - 20) / 20] x 100
Subtract the new number by the original number
850 - 20 = 830
830 ÷ 20 = 41.5
41.5 x 100 = 4150%
Example