Ответ:

  1. \(\frac{7}{10}+\frac{1}{10}=\frac{8}{10}=\frac{4}{5}\).
  2. \(\frac{7}{12}+\frac{1}{4}=\frac{7}{12}+\frac{3}{12}=\frac{10}{12}=\frac{5}{6}\).
  3. \(\frac{1}{5}+\frac{2}{15}=\frac{3}{15}+\frac{2}{15}=\frac{1}{3}\).
  4. \(\frac{5}{6}+\frac{1}{9}=\frac{15}{18}+\frac{2}{18}=\frac{17}{18}\).
  5. \(\frac{2}{9}+\frac{1}{12}=\frac{8}{36}+\frac{3}{36}=\frac{11}{36}\).
  6. \(\frac{7}{24}+\frac{1}{60}=\frac{35}{120}+\frac{2}{120}=\frac{37}{120}\).
  7. \(\frac{1}{42}+\frac{2}{63}=\frac{3}{126}+\frac{4}{126}=\frac{7}{126}=\frac{1}{18}\).
  8. \(\frac{5}{12}+\frac{3}{20}=\frac{25}{60}+\frac{9}{60}=\frac{17}{30}\).

Ответ: а) \(\frac{4}{5}\); б) \(\frac{5}{6}\); в) \(\frac{1}{3}\); г) \(\frac{17}{18}\); д) \(\frac{11}{36}\); е) \(\frac{37}{120}\); ж) \(\frac{1}{18}\); з) \(\frac{17}{30}\).