2) \(\frac{4}{5}+\frac{3}{10}\); \(\frac{5}{7}+\frac{1}{2}\); \(\frac{5}{8}+\frac{3}{4}\).

1. \(\frac{4}{5}=\frac{8}{10}\).
   \(\frac{8}{10}+\frac{3}{10}=\frac{11}{10}=1\frac{1}{10}\).
2. Общий знаменатель — 14:
   \(\frac{5}{7}=\frac{10}{14}\), \(\frac{1}{2}=\frac{7}{14}\).
   \(\frac{10}{14}+\frac{7}{14}=\frac{17}{14}=1\frac{3}{14}\).
3. \(\frac{3}{4}=\frac{6}{8}\).
   \(\frac{5}{8}+\frac{6}{8}=\frac{11}{8}=1\frac{3}{8}\).

Ответ: \(1\frac{1}{10};\ 1\frac{3}{14};\ 1\frac{3}{8}\).