Ответ:

  1. \(\frac{3}{7}+\frac{1}{14}=\frac{6}{14}+\frac{1}{14}=\frac{7}{14}=\frac{1}{2}\).
  2. \(\frac{4}{25}-\frac{11}{15}=\frac{12}{75}-\frac{55}{75}=-\frac{43}{75}\).
  3. \(-\frac{11}{14}\cdot\frac{21}{22}=-\frac{3}{4}\).
  4. \(\frac{12}{19}:\frac{9}{38}=\frac{12}{19}\cdot\frac{38}{9}=\frac{8}{3}\).
  5. \(7\frac{4}{15}+3\frac{11}{12}=10+\frac{16}{60}+\frac{55}{60}=10\frac{71}{60}=11\frac{11}{60}\).
  6. \(3\frac{5}{12}-2\frac{5}{6}=3\frac{5}{12}-2\frac{10}{12}=1-\frac{5}{12}=\frac{7}{12}\).
  7. \(3\frac{3}{13}\cdot4=\frac{42}{13}\cdot4=\frac{168}{13}=12\frac{12}{13}\).
  8. \(3\frac{7}{9}:17=\frac{34}{9}:17=\frac{34}{9}\cdot\frac{1}{17}=\frac{2}{9}\).

Ответ: а) \(\frac{1}{2}\); б) \(-\frac{43}{75}\); в) \(-\frac{3}{4}\); г) \(\frac{8}{3}\); д) \(11\frac{11}{60}\); е) \(\frac{7}{12}\); ж) \(12\frac{12}{13}\); з) \(\frac{2}{9}\).