Answer:
17
Explanation:
First, you can change the equation to 12 1/2 + 4 1/2, as subtracting a negative number is actually adding it. Then, if easier, the mixed numbers can be changed to improper fractions -- 12 1/2 = 25/2 and 4 1/2 = 9/2. Then add; 25/2 + 9/2 = 34/2, and 34 divided by 2 is 17.