-98.81% is the change from 840 to 10
Calculation steps:
[( 10 - 840 ) ÷ 840] x 100 = -98.81%
Formula
Percentage change = [(10 - 840) / 840] x 100
Subtract the new number by the original number
10 - 840 = -830
-830 ÷ 840 = -0.9880952380952381
-0.9880952380952381 x 100 = -98.81%