-10% is the change from 400 to 360
Calculation steps:
[( 360 - 400 ) ÷ 400] x 100 = -10%
Formula
Percentage change = [(360 - 400) / 400] x 100
Subtract the new number by the original number
360 - 400 = -40
-40 ÷ 400 = -0.1
-0.1 x 100 = -10%
Example