-5% is the change from 820 to 779
Calculation steps:
[( 779 - 820 ) ÷ 820] x 100 = -5%
Formula
Percentage change = [(779 - 820) / 820] x 100
Subtract the new number by the original number
779 - 820 = -41
-41 ÷ 820 = -0.05
-0.05 x 100 = -5%
Example