I think the answer is c but I am not for sure
If a+b= 2+11 then your sum will be 13.
heres an example...
If you have eleven dollars and I give you 2 more you can simply count up 2 more from 11 leaving you at 13.
you're welcome.
That is your answer if it is wrong i will try to fix it
Answer:
1
Step-by-step explanation:
9-8=1