It's just not realistic to present a list of 12 math questions and ask for the answers to all of them at once. Please post only one question at a time and please share your thoughts about how to solve that question.
I'll focus on one problem: 7 2/3 + 2 7/12
Here the LCD (lowest common denominator) is 12. 7 2/3 becomes 7 8/12.
Add 7 8/12 and 2 7/12:
7 8/12
+2 7/12
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9 15/12 15/12 is not a proper fraction. Write it as 1 3/12, or 1 1/4.
Then your 9 15/12 becomes (9+1) 1/4, or 10 1/4.
