Ответ:

а) \(\frac{2}{9}+\frac{6}{9}-\frac{3}{9}=\frac{2+6-3}{9}=\frac{5}{9}\).

б) \(8\frac{25}{27}-\left(3\frac{8}{27}+2\frac{3}{27}\right)=8\frac{25}{27}-5\frac{11}{27}=3\frac{14}{27}\).

в) \(\left(8\frac{3}{17}-7\frac{15}{17}\right)+3\frac{16}{17}=\frac{139}{17}-\frac{134}{17}+\frac{67}{17}=\frac{72}{17}=4\frac{4}{17}\).

Ответ: а) \(\frac{5}{9}\); б) \(3\frac{14}{27}\); в) \(4\frac{4}{17}\).