-20% is the change from 300 to 240
Calculation steps:
[( 240 - 300 ) ÷ 300] x 100 = -20%
Formula
Percentage change = [(240 - 300) / 300] x 100
Subtract the new number by the original number
240 - 300 = -60
-60 ÷ 300 = -0.2
-0.2 x 100 = -20%
Example