1) \(\frac{2}{3}+\frac{5}{9}\); \(\frac{3}{8}+\frac{1}{2}\); \(\frac{1}{14}+\frac{3}{7}\).

1. Приводим к общему знаменателю: \(\frac{2}{3}=\frac{6}{9}\).
   \(\frac{6}{9}+\frac{5}{9}=\frac{11}{9}=1\frac{2}{9}\).
2. \(\frac{1}{2}=\frac{4}{8}\).
   \(\frac{3}{8}+\frac{4}{8}=\frac{7}{8}\).
3. \(\frac{3}{7}=\frac{6}{14}\).
   \(\frac{1}{14}+\frac{6}{14}=\frac{7}{14}=\frac{1}{2}\).

Ответ: \(1\frac{2}{9};\ \frac{7}{8};\ \frac{1}{2}\).