Answer: +19
Step-by-step explanation: In this problem we are asked to evaluate 9 - (-12).
To subtract these integers, it's important to understand that when we have minus a negative, we can change it to plus a positive.
So 9 - (-12) can be changed to 9 + (+12) or 9 + 12 which gives us a sum of 21.
Therefore, 9 - (-12) = +21.
Notice that I put the '+' sign in front of the 21. Although this is optional, it's a good idea to do especially when adding and subtracting positives and negatives. All it shows is that our answer is positive.
