It is like if you have two number lines. Then one has a pointer at 0, and the other one has the pointer facing at 2 then it will be lesser because the first one has 0 or if it turned around it would be greater. If it is equal then it would have the same number, but watch out if it is a negative number.
Because like terms you add or subtract together to make it easier to do the problem. just like you do with whole numbers. you add an subtract to make the answer simpler.
She will make $182 for 13 hours of work