So firstly, do the multiplications:
![(42)/(8)+(35)/(6)+(10)/(12)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/ck7wlp7csy3d18o2r4pc45faofuxvq1czu.png)
Next, we want to find the LCM, or lowest common multiple, between the 3 denominators. In this case, it is 24. Multiply 42/8 by 3/3, 35/6 by 4/4, and 10/12 by 2/2:
![(42)/(8)*(3)/(3)=(126)/(24)\\ \\ (35)/(6)*(4)/(4)=(140)/(24)\\ \\ (10)/(12)*(2)/(2)=(20)/(24)\\ \\ (126)/(24)+(140)/(24)+(20)/(24)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/kf91a3lnjl446g87jruu9avc1jrpq9cypw.png)
Now add up all the numerators together to get 286/24, which can be simplified to 143/12 when divided by 2 on the numerator and denominator.
In short, 143/12 is the answer.