-97.62% is the change from 420 to 10
Calculation steps:
[( 10 - 420 ) ÷ 420] x 100 = -97.62%
Formula
Percentage change = [(10 - 420) / 420] x 100
Subtract the new number by the original number
10 - 420 = -410
-410 ÷ 420 = -0.9761904761904762
-0.9761904761904762 x 100 = -97.62%