-85% is the change from 280 to 42
Calculation steps:
[( 42 - 280 ) ÷ 280] x 100 = -85%
Formula
Percentage change = [(42 - 280) / 280] x 100
Subtract the new number by the original number
42 - 280 = -238
-238 ÷ 280 = -0.85
-0.85 x 100 = -85%
Example