-19% is the change from 400 to 324
Calculation steps:
[( 324 - 400 ) ÷ 400] x 100 = -19%
Formula
Percentage change = [(324 - 400) / 400] x 100
Subtract the new number by the original number
324 - 400 = -76
-76 ÷ 400 = -0.19
-0.19 x 100 = -19%
Example