-49.28% is the change from 830 to 421
Calculation steps:
[( 421 - 830 ) ÷ 830] x 100 = -49.28%
Formula
Percentage change = [(421 - 830) / 830] x 100
Subtract the new number by the original number
421 - 830 = -409
-409 ÷ 830 = -0.4927710843373494
-0.4927710843373494 x 100 = -49.28%