-12.5% is the change from 480 to 420
Calculation steps:
[( 420 - 480 ) ÷ 480] x 100 = -12.5%
Formula
Percentage change = [(420 - 480) / 480] x 100
Subtract the new number by the original number
420 - 480 = -60
-60 ÷ 480 = -0.125
-0.125 x 100 = -12.5%