-82% is the change from 450 to 81
Calculation steps:
[( 81 - 450 ) ÷ 450] x 100 = -82%
Formula
Percentage change = [(81 - 450) / 450] x 100
Subtract the new number by the original number
81 - 450 = -369
-369 ÷ 450 = -0.82
-0.82 x 100 = -82%
Example