-78.43% is the change from 255 to 55
Calculation steps:
[( 55 - 255 ) ÷ 255] x 100 = -78.43%
Formula
Percentage change = [(55 - 255) / 255] x 100
Subtract the new number by the original number
55 - 255 = -200
-200 ÷ 255 = -0.7843137254901961
-0.7843137254901961 x 100 = -78.43%