9 7/8 + 2 7/8

I get 11 14/8

Is that right

79/8 + 23/8 + 0 =

= 51/4 + 0 =
= 51/4 = 12 3/4

technically , you are right

but, ...
in your mixed number answer, we don't have improper fractions in the answer

so 11 14/8
= 11 + 1 6/8
= 12 3/4 like Tom had given you (I don't understand why Tom added the 0 at the end)