-82% is the change from 50 to 9
Calculation steps:
[( 9 - 50 ) ÷ 50] x 100 = -82%
Formula
Percentage change = [(9 - 50) / 50] x 100
Subtract the new number by the original number
9 - 50 = -41
-41 ÷ 50 = -0.82
-0.82 x 100 = -82%
Example