-90.24% is the change from 840 to 82
Calculation steps:
[( 82 - 840 ) ÷ 840] x 100 = -90.24%
Formula
Percentage change = [(82 - 840) / 840] x 100
Subtract the new number by the original number
82 - 840 = -758
-758 ÷ 840 = -0.9023809523809524
-0.9023809523809524 x 100 = -90.24%