Answer:
-4
Explanation:
Remark
I take the question to be 8 + (-12). If it's not, and the 3 numbers on top and the 6 numbers actually mean something, please leave a note to tell us what they mean.
If the question is as I've stated it then the answer is - 4. Think money. If you have 8 dollars and spend 12 you owe someone 4 dollars. A debt is a minus number from your point of view.