50% is the change from 18 to 27
Calculation steps:
[( 27 - 18 ) ÷ 18] x 100 = 50%
Formula
Percentage change = [(27 - 18) / 18] x 100
Subtract the new number by the original number
27 - 18 = 9
9 ÷ 18 = 0.5
0.5 x 100 = 50%
Example