Ответ:

  1. \(\frac{3}{8}+\frac{4}{9}=\frac{27}{72}+\frac{32}{72}=\frac{59}{72}\).
  2. \(\frac{7}{12}-\frac{3}{8}=\frac{14}{24}-\frac{9}{24}=\frac{5}{24}\).
  3. \(2\frac{5}{8}+1\frac{1}{10}=3+\frac{25}{40}+\frac{4}{40}=3\frac{29}{40}\).
  4. \(6\frac{7}{10}-4\frac{5}{12}=2+\frac{42}{60}-\frac{25}{60}=2\frac{17}{60}\).

Ответ: 1) \(\frac{59}{72}\); 2) \(\frac{5}{24}\); 3) \(3\frac{29}{40}\); 4) \(2\frac{17}{60}\).