-4.83% is the change from 870 to 828
Calculation steps:
[( 828 - 870 ) ÷ 870] x 100 = -4.83%
Formula
Percentage change = [(828 - 870) / 870] x 100
Subtract the new number by the original number
828 - 870 = -42
-42 ÷ 870 = -0.04827586206896552
-0.04827586206896552 x 100 = -4.83%