-84% is the change from 400 to 64
Calculation steps:
[( 64 - 400 ) ÷ 400] x 100 = -84%
Formula
Percentage change = [(64 - 400) / 400] x 100
Subtract the new number by the original number
64 - 400 = -336
-336 ÷ 400 = -0.84
-0.84 x 100 = -84%
Example