-51.9% is the change from 840 to 404
Calculation steps:
[( 404 - 840 ) ÷ 840] x 100 = -51.9%
Formula
Percentage change = [(404 - 840) / 840] x 100
Subtract the new number by the original number
404 - 840 = -436
-436 ÷ 840 = -0.5190476190476191
-0.5190476190476191 x 100 = -51.9%