-10% is the change from 80 to 72
Calculation steps:
[( 72 - 80 ) ÷ 80] x 100 = -10%
Formula
Percentage change = [(72 - 80) / 80] x 100
Subtract the new number by the original number
72 - 80 = -8
-8 ÷ 80 = -0.1
-0.1 x 100 = -10%
Example