-84% is the change from 500 to 80
Calculation steps:
[( 80 - 500 ) ÷ 500] x 100 = -84%
Formula
Percentage change = [(80 - 500) / 500] x 100
Subtract the new number by the original number
80 - 500 = -420
-420 ÷ 500 = -0.84
-0.84 x 100 = -84%
Example