This problem reads 12 + (-10).
When we are adding a positive number to a negative number,
we can slo rewrite this as 12 - 10.
When you are learning to add and subtract integers, I find it helpful to start with an easy diagram to visualize what's going on.
In the diagram below, I represented the 12 in this problem as 12 pluses and I represented the -10 as 10 minuses.
Now, a plus and a minus will equal 0.
So cross out one plus and one minus until you can't do it anymore.
You can see that you end up 2 pluses.
That 2 represents your answer to this problem.
So 12 + (-10) simplifies to +2.