Ответ:

  1. \(\frac{1}{12}+\frac{3}{4}=\frac{1}{12}+\frac{9}{12}=\frac{10}{12}=\frac{5}{6}\).
  2. \(2\frac{1}{4}:\frac{1}{6}=\frac{9}{4}\cdot6=\frac{54}{4}=13\frac{1}{2}\).
  3. \(2-1\frac{3}{7}=2-\frac{10}{7}=\frac{14}{7}-\frac{10}{7}=\frac{4}{7}\).
  4. \(12\cdot\frac{3}{4}=9\).

Ответ: а) \(\frac{5}{6}\); б) \(13\frac{1}{2}\); в) \(\frac{4}{7}\); г) \(9\).