Ответ:

  1. а) \(\frac{3}{4}+\frac{5}{6}=\frac{9}{12}+\frac{10}{12}=\frac{19}{12}=1\frac{7}{12}\).

  2. б) \(7-\frac{5}{9}=6\frac{9}{9}-\frac{5}{9}=6\frac{4}{9}\).

  3. в) \(3\frac{2}{5}+1\frac{3}{4}=4+\frac{8}{20}+\frac{15}{20}=4+\frac{23}{20}=5\frac{3}{20}\).

  4. г) \(5\frac{1}{6}-2\frac{3}{4}=4\frac{14}{12}-2\frac{9}{12}=2\frac{5}{12}\).