-99.17% is the change from 840 to 7
Calculation steps:
[( 7 - 840 ) ÷ 840] x 100 = -99.17%
Formula
Percentage change = [(7 - 840) / 840] x 100
Subtract the new number by the original number
7 - 840 = -833
-833 ÷ 840 = -0.9916666666666667
-0.9916666666666667 x 100 = -99.17%