-82.5% is the change from 400 to 70
Calculation steps:
[( 70 - 400 ) ÷ 400] x 100 = -82.5%
Formula
Percentage change = [(70 - 400) / 400] x 100
Subtract the new number by the original number
70 - 400 = -330
-330 ÷ 400 = -0.825
-0.825 x 100 = -82.5%
Example