Answer:
Step-by-step explanation:
ok if you mean 9 + 10 then it's 19, but if you mean -9 + -10 then it's -19 and if you mean 9 - 9 + 10 - 10 then it's 0
i'm just giving you all the answers because the way you worded the question it is a bit hard to tell.
Hope that helps
