8 3/4 + 9 5/9 Add 8 and 9
17 + 3*9/4*9 + 5*4/9*4 Find common denominator
17 + 27/36 + 20/36 Add
17 + 47/36 Convert into mixed fraction
17 + 1 11/36 Simplify mixed fraction
18 11/36. Answer
If you need the decimal form, it is 18.31. But other than that, the answer is 18 11/36.