900% is the change from 39 to 390
Calculation steps:
[( 390 - 39 ) ÷ 39] x 100 = 900%
Formula
Percentage change = [(390 - 39) / 39] x 100
Subtract the new number by the original number
390 - 39 = 351
351 ÷ 39 = 9
9 x 100 = 900%
Example