Ответ:

а)

Преобразуем смешанные числа и десятичные дроби:

\(8\frac{7}{12}=\frac{309}{36}\), \(2\frac{17}{36}=\frac{89}{36}\), поэтому
\(8\frac{7}{12}-2\frac{17}{36}=\frac{309-89}{36}=\frac{220}{36}=\frac{55}{9}\).

\(2,7=\frac{27}{10}\), \(0,65=\frac{13}{20}\), \(4\frac{1}{3}=\frac{13}{3}\).

\(\frac{55}{9}\cdot\frac{27}{10}-\frac{13}{3}:\frac{13}{20}=\frac{33}{2}-\frac{20}{3}=\frac{99-40}{6}=\frac{59}{6}\).

б)

\(6\frac{2}{3}=\frac{20}{3}\), \(0,2=\frac{1}{5}\), \(3\frac{5}{9}=\frac{32}{9}\), \(8\frac{1}{15}=\frac{121}{15}\).

\(\left(\frac{20}{3}:\frac{1}{5}:\frac{1}{6}-\frac{32}{9}\right):2+\frac{121}{15}\)

\(=\left(\frac{20}{3}\cdot5\cdot6-\frac{32}{9}\right):2+\frac{121}{15}\)

\(=\left(200-\frac{32}{9}\right):2+\frac{121}{15}=\frac{1768}{9}:2+\frac{121}{15}\)

\(=\frac{884}{9}+\frac{121}{15}=\frac{4420+363}{45}=\frac{4783}{45}=106\frac{13}{45}\).

Ответ: а) \(\frac{59}{6}\); б) \(106\frac{13}{45}\).