\[- 10,5 - 6\frac{5}{6} = - 10\frac{1^{\backslash 3}}{2} - 6\frac{5}{6} =\]
\[= - 10\frac{3}{6} - 6\frac{5}{6} = - 16\frac{8}{6} =\]
\[= - 16\frac{4}{3} = - 17\frac{1}{3}.\]