70% is the change from 40 to 68
Calculation steps:
[( 68 - 40 ) ÷ 40] x 100 = 70%
Formula
Percentage change = [(68 - 40) / 40] x 100
Subtract the new number by the original number
68 - 40 = 28
28 ÷ 40 = 0.7
0.7 x 100 = 70%
Example