-93.9% is the change from 820 to 50
Calculation steps:
[( 50 - 820 ) ÷ 820] x 100 = -93.9%
Formula
Percentage change = [(50 - 820) / 820] x 100
Subtract the new number by the original number
50 - 820 = -770
-770 ÷ 820 = -0.9390243902439024
-0.9390243902439024 x 100 = -93.9%