-84.9% is the change from 821 to 124
Calculation steps:
[( 124 - 821 ) ÷ 821] x 100 = -84.9%
Formula
Percentage change = [(124 - 821) / 821] x 100
Subtract the new number by the original number
124 - 821 = -697
-697 ÷ 821 = -0.8489646772228989
-0.8489646772228989 x 100 = -84.9%