1900% is the change from 20 to 400
Calculation steps:
[( 400 - 20 ) ÷ 20] x 100 = 1900%
Formula
Percentage change = [(400 - 20) / 20] x 100
Subtract the new number by the original number
400 - 20 = 380
380 ÷ 20 = 19
19 x 100 = 1900%
Example