2. Вычислите: 1) \(\frac{5}{7}+\frac{1}{4}\); 2) \(\frac{11}{18}-\frac{4}{9}\); 3) \(\frac{7}{45}+\frac{9}{20}\); 4) \(\frac{11}{16}-\frac{5}{12}\); 5) \(\frac{8}{15}-\frac{4}{9}\); 6) \(\frac{7}{10}+\frac{7}{15}\).

1. \(\frac{5}{7}+\frac{1}{4}=\frac{20+7}{28}=\frac{27}{28}\).
2. \(\frac{11}{18}-\frac{4}{9}=\frac{11}{18}-\frac{8}{18}=\frac{1}{6}\).
3. \(\frac{7}{45}+\frac{9}{20}=\frac{28+81}{180}=\frac{109}{180}\).
4. \(\frac{11}{16}-\frac{5}{12}=\frac{33-20}{48}=\frac{13}{48}\).
5. \(\frac{8}{15}-\frac{4}{9}=\frac{24-20}{45}=\frac{4}{45}\).
6. \(\frac{7}{10}+\frac{7}{15}=\frac{21+14}{30}=\frac{7}{6}=1\frac{1}{6}\).

Ответ: 1) \(\frac{27}{28}\); 2) \(\frac{1}{6}\); 3) \(\frac{109}{180}\); 4) \(\frac{13}{48}\); 5) \(\frac{4}{45}\); 6) \(1\frac{1}{6}\).