5 3/4 + 6 2/4= 11 10/8 then I am not sure what to do from here?
5 3/4 + 6 2/4
= 23/4 + 26/4
= 49/4 or 12 1/4
don't know why you switched the denominators to 8, they were both 4, so that is your LCD
from your answer of 11 10/8
the 10/8 = 5/4 = 1 1/4
add that to your 11 and you would have the correct answer.