-20% is the change from 525 to 420
Calculation steps:
[( 420 - 525 ) ÷ 525] x 100 = -20%
Formula
Percentage change = [(420 - 525) / 525] x 100
Subtract the new number by the original number
420 - 525 = -105
-105 ÷ 525 = -0.2
-0.2 x 100 = -20%
Example