Ответ:

  1. \(3\frac{7}{11}+\frac{2}{11}=3\frac{9}{11}\).
  2. \(6\frac{2}{15}+3\frac{9}{15}=9\frac{11}{15}\).
  3. \(8+3\frac{7}{8}=11\frac{7}{8}\).
  4. \(4\frac{5}{9}+3=7\frac{5}{9}\).
  5. \(7\frac{13}{20}+8\frac{7}{20}=15\).
  6. \(2\frac{18}{25}+7\frac{8}{25}=9\frac{26}{25}=10\frac{1}{25}\).

Ответ: а) \(3\frac{9}{11}\); б) \(9\frac{11}{15}\); в) \(11\frac{7}{8}\); г) \(7\frac{5}{9}\); д) \(15\); е) \(10\frac{1}{25}\).