-40.48% is the change from 420 to 250
Calculation steps:
[( 250 - 420 ) ÷ 420] x 100 = -40.48%
Formula
Percentage change = [(250 - 420) / 420] x 100
Subtract the new number by the original number
250 - 420 = -170
-170 ÷ 420 = -0.40476190476190477
-0.40476190476190477 x 100 = -40.48%