50% is the change from 40 to 60
Calculation steps:
[( 60 - 40 ) ÷ 40] x 100 = 50%
Formula
Percentage change = [(60 - 40) / 40] x 100
Subtract the new number by the original number
60 - 40 = 20
20 ÷ 40 = 0.5
0.5 x 100 = 50%
Example