50% is the change from 270 to 405
Calculation steps:
[( 405 - 270 ) ÷ 270] x 100 = 50%
Formula
Percentage change = [(405 - 270) / 270] x 100
Subtract the new number by the original number
405 - 270 = 135
135 ÷ 270 = 0.5
0.5 x 100 = 50%
Example