350% is the change from 18 to 81
Calculation steps:
[( 81 - 18 ) ÷ 18] x 100 = 350%
Formula
Percentage change = [(81 - 18) / 18] x 100
Subtract the new number by the original number
81 - 18 = 63
63 ÷ 18 = 3.5
3.5 x 100 = 350%
Example