900% is the change from 9 to 90
Calculation steps:
[( 90 - 9 ) ÷ 9] x 100 = 900%
Formula
Percentage change = [(90 - 9) / 9] x 100
Subtract the new number by the original number
90 - 9 = 81
81 ÷ 9 = 9
9 x 100 = 900%
Example