Hey there!
We can think of this as a number line. To the left of zero is negative numbers, and to the right is positive. Therefore, -12 is 12 to the left. However, whenever you add something, you go that value to the right. We can't forget that in negatives when we go closer to zero, the numbers get smaller but the values get bigger. We go to the right four, and get -8. So, our answer is negative.
Hope this helps!
