2150% is the change from 40 to 900
Calculation steps:
[( 900 - 40 ) ÷ 40] x 100 = 2150%
Formula
Percentage change = [(900 - 40) / 40] x 100
Subtract the new number by the original number
900 - 40 = 860
860 ÷ 40 = 21.5
21.5 x 100 = 2150%
Example