-50% is the change from 12 to 6
Calculation steps:
[( 6 - 12 ) ÷ 12] x 100 = -50%
Formula
Percentage change = [(6 - 12) / 12] x 100
Subtract the new number by the original number
6 - 12 = -6
-6 ÷ 12 = -0.5
-0.5 x 100 = -50%
Example