-85% is the change from 40 to 6
Calculation steps:
[( 6 - 40 ) ÷ 40] x 100 = -85%
Formula
Percentage change = [(6 - 40) / 40] x 100
Subtract the new number by the original number
6 - 40 = -34
-34 ÷ 40 = -0.85
-0.85 x 100 = -85%
Example