-85% is the change from 800 to 120
Calculation steps:
[( 120 - 800 ) ÷ 800] x 100 = -85%
Formula
Percentage change = [(120 - 800) / 800] x 100
Subtract the new number by the original number
120 - 800 = -680
-680 ÷ 800 = -0.85
-0.85 x 100 = -85%
Example