-40.24% is the change from 420 to 251
Calculation steps:
[( 251 - 420 ) ÷ 420] x 100 = -40.24%
Formula
Percentage change = [(251 - 420) / 420] x 100
Subtract the new number by the original number
251 - 420 = -169
-169 ÷ 420 = -0.4023809523809524
-0.4023809523809524 x 100 = -40.24%