-30% is the change from 10 to 7
Calculation steps:
[( 7 - 10 ) ÷ 10] x 100 = -30%
Formula
Percentage change = [(7 - 10) / 10] x 100
Subtract the new number by the original number
7 - 10 = -3
-3 ÷ 10 = -0.3
-0.3 x 100 = -30%
Example