97.62% is the change from 420 to 830
Calculation steps:
[( 830 - 420 ) ÷ 420] x 100 = 97.62%
Formula
Percentage change = [(830 - 420) / 420] x 100
Subtract the new number by the original number
830 - 420 = 410
410 ÷ 420 = 0.9761904761904762
0.9761904761904762 x 100 = 97.62%