\[\boxed{\text{П.85.}}\]
\[\textbf{а)}\ 10\frac{8}{13} + 6\frac{3}{13} - 3\frac{9}{13} =\]
\[= 16\frac{11}{13} - 3\frac{9}{13} = 13\frac{2}{13}\ \]
\[\textbf{б)}\ 8\frac{14}{20} - \left( 5\frac{7}{20} - 2\frac{3}{20} \right) =\]
\[= 8\frac{14}{20} - 3\frac{4}{20} = 5\frac{10}{20} = 5\frac{1}{2}\ \]
\[\textbf{в)}\ 14\frac{27}{45} - 3\frac{8}{45} + 5\frac{6}{45} =\]
\[= 11\frac{19}{45} + 5\frac{6}{45} = 16\frac{25}{45} = 16\frac{5}{9}\]
\[\textbf{г)}\ 10\frac{22}{23} - \left( 5\frac{4}{23} - 4\frac{5}{23} \right) =\]
\[= 10\frac{22}{23} - 5\frac{4}{23} + 4\frac{5}{23} =\]
\[= 5\frac{18}{23} + 4\frac{5}{23} = 9\frac{23}{23} = 10\]