39900% is the change from 2 to 800
Calculation steps:
[( 800 - 2 ) ÷ 2] x 100 = 39900%
Formula
Percentage change = [(800 - 2) / 2] x 100
Subtract the new number by the original number
800 - 2 = 798
798 ÷ 2 = 399
399 x 100 = 39900%
Example