Answer :

6, 7/8 + 4, 5/8 = 10, 12/8 = 11, 4/8 = 11, 1/2 (1/2 = 4/8 simplest form)
Hope that made sense :)
[tex]6\frac{7}{8}+4\frac{5}{8}\\----------------\\6+4=10\\\\\frac{7}{8}+\frac{5}{8}=\frac{7+5}{8}=\frac{12}{8}=1\frac{4}{8}=1\frac{1}{2}\\\\10+1\frac{1}{2}=11\frac{1}{2}\\\\====================\\\\6\frac{7}{8}+4\frac{5}{8}=11\frac{1}{2}[/tex]