Ответ:

  1. \(\frac{3}{10}-\frac{2}{15}=\frac{9}{30}-\frac{4}{30}=\frac{5}{30}=\frac{1}{6}\).
  2. \(1\frac{4}{7}+2\frac{3}{21}=1\frac{4}{7}+2\frac{1}{7}=3\frac{5}{7}\).
  3. \(5\frac{1}{4}+3\frac{8}{11}=8+\frac{11}{44}+\frac{32}{44}=8\frac{43}{44}\).
  4. \(4-\frac{2}{3}=3\frac{1}{3}\).
  5. \(5\frac{1}{4}-3\frac{7}{8}=5\frac{2}{8}-3\frac{7}{8}=1\frac{3}{8}\).

Ответ: а) \(\frac{1}{6}\); б) \(3\frac{5}{7}\); в) \(8\frac{43}{44}\); г) \(3\frac{1}{3}\); д) \(1\frac{3}{8}\).