350% is the change from 20 to 90
Calculation steps:
[( 90 - 20 ) ÷ 20] x 100 = 350%
Formula
Percentage change = [(90 - 20) / 20] x 100
Subtract the new number by the original number
90 - 20 = 70
70 ÷ 20 = 3.5
3.5 x 100 = 350%
Example