Выполните действия: 1) \(\frac{5}{9}+\frac{1}{9}\); 2) \(\frac{8}{17}-\frac{2}{17}\); 3) \(\frac{8}{25}-\frac{3}{25}+\frac{9}{25}\); 4) \(\frac{21}{57}+\frac{31}{57}-\frac{9}{57}\).

1. \(\frac{5}{9}+\frac{1}{9}=\frac{6}{9}=\frac{2}{3}\).
2. \(\frac{8}{17}-\frac{2}{17}=\frac{6}{17}\).
3. \(\frac{8-3+9}{25}=\frac{14}{25}\).
4. \(\frac{21+31-9}{57}=\frac{43}{57}\).

Ответ: 1) \(\frac{2}{3}\); 2) \(\frac{6}{17}\); 3) \(\frac{14}{25}\); 4) \(\frac{43}{57}\).