The answer would be 12
The lines one the side represent absolute value. If you don’t know what absolute value you then imagine a number line. And think of 18 and -6. If you count what -6 is from 0 you would count the units until -6 so it would be 6 units from 0.
What you would do with this that you would make 18 into a regular 18 and make -6 into 6 because it has a distance of 6 from 0. You then do 18-6 which would be 12.
