8 11per12 - 1 1per6 - 2 1per8 =

[tex]8 \frac{11}{12} - \: 1 \frac{1}{6} - 2 \frac{1}{8} \\ = 8 \frac{22}{24} - 1 \frac{4}{24} - 2 \frac{3}{24} \\ = 5 \frac{15}{24} \\ = 5 \frac{3}{8} [/tex]