-55% is the change from 400 to 180
Calculation steps:
[( 180 - 400 ) ÷ 400] x 100 = -55%
Formula
Percentage change = [(180 - 400) / 400] x 100
Subtract the new number by the original number
180 - 400 = -220
-220 ÷ 400 = -0.55
-0.55 x 100 = -55%
Example