-80.24% is the change from 420 to 83
Calculation steps:
[( 83 - 420 ) ÷ 420] x 100 = -80.24%
Formula
Percentage change = [(83 - 420) / 420] x 100
Subtract the new number by the original number
83 - 420 = -337
-337 ÷ 420 = -0.8023809523809524
-0.8023809523809524 x 100 = -80.24%