-60% is the change from 20 to 8
Calculation steps:
[( 8 - 20 ) ÷ 20] x 100 = -60%
Formula
Percentage change = [(8 - 20) / 20] x 100
Subtract the new number by the original number
8 - 20 = -12
-12 ÷ 20 = -0.6
-0.6 x 100 = -60%
Example