19900% is the change from 2 to 400
Calculation steps:
[( 400 - 2 ) ÷ 2] x 100 = 19900%
Formula
Percentage change = [(400 - 2) / 2] x 100
Subtract the new number by the original number
400 - 2 = 398
398 ÷ 2 = 199
199 x 100 = 19900%
Example