101.9% is the change from 421 to 850
Calculation steps:
[( 850 - 421 ) ÷ 421] x 100 = 101.9%
Formula
Percentage change = [(850 - 421) / 421] x 100
Subtract the new number by the original number
850 - 421 = 429
429 ÷ 421 = 1.0190023752969122
1.0190023752969122 x 100 = 101.9%