Ответ:

  1. \(\frac{1}{3}-\frac{1}{6}=\frac{2}{6}-\frac{1}{6}=\frac{1}{6}\).
  2. \(\frac{3}{6}-\frac{1}{7}=\frac{1}{2}-\frac{1}{7}=\frac{7}{14}-\frac{2}{14}=\frac{5}{14}\).
  3. \(\frac{8}{15}-\frac{1}{2}=\frac{16}{30}-\frac{15}{30}=\frac{1}{30}\).
  4. \(\frac{4}{7}-\frac{3}{10}=\frac{40}{70}-\frac{21}{70}=\frac{19}{70}\).

Ответ: а) \(\frac{1}{6}\); б) \(\frac{5}{14}\); в) \(\frac{1}{30}\); г) \(\frac{19}{70}\).