Determine the lowest common nominated for each sum or difference

Answer:
See below.
Step-by-step explanation:
13/24 + 7/12: LCD is 24
7/6 + (-5/12): LCD is 12
-3/4 - 2/3: LCD is 12
5 - 7/10: LCD is 10
1/8 - 5/3: LCD is 24
3/2 - 4/5: LCD is 10