-50% is the change from 856 to 428
Calculation steps:
[( 428 - 856 ) ÷ 856] x 100 = -50%
Formula
Percentage change = [(428 - 856) / 856] x 100
Subtract the new number by the original number
428 - 856 = -428
-428 ÷ 856 = -0.5
-0.5 x 100 = -50%
Example