-82.81% is the change from 320 to 55
Calculation steps:
[( 55 - 320 ) ÷ 320] x 100 = -82.81%
Formula
Percentage change = [(55 - 320) / 320] x 100
Subtract the new number by the original number
55 - 320 = -265
-265 ÷ 320 = -0.828125
-0.828125 x 100 = -82.81%