3. Выполните действия: 13/18 + 7/12; 5/7 − 3/5; 5/6 − 3/8 − 1/12.

1. \(\frac{13}{18}+\frac{7}{12}=\frac{26}{36}+\frac{21}{36}=\frac{47}{36}=1\frac{11}{36}\).
2. \(\frac{5}{7}-\frac{3}{5}=\frac{25}{35}-\frac{21}{35}=\frac{4}{35}\).
3. \(\frac{5}{6}-\frac{3}{8}-\frac{1}{12}=\frac{20}{24}-\frac{9}{24}-\frac{2}{24}=\frac{9}{24}=\frac{3}{8}\).

Ответ: \(1\frac{11}{36};\ \frac{4}{35};\ \frac{3}{8}\).