Задание 3. Выполните действия: 1) 5/12 + 7/18; 2) 7/10 − 3/8; 3) 5/6 + 3/8; 4) 11/15 − 5/12; 5) 3/4 + 5/14; 6) 9/20 − 7/30.

1. \(\frac{5}{12}+\frac{7}{18}=\frac{15}{36}+\frac{14}{36}=\frac{29}{36}\).
2. \(\frac{7}{10}-\frac{3}{8}=\frac{28}{40}-\frac{15}{40}=\frac{13}{40}\).
3. \(\frac{5}{6}+\frac{3}{8}=\frac{20}{24}+\frac{9}{24}=\frac{29}{24}=1\frac{5}{24}\).
4. \(\frac{11}{15}-\frac{5}{12}=\frac{44}{60}-\frac{25}{60}=\frac{19}{60}\).
5. \(\frac{3}{4}+\frac{5}{14}=\frac{21}{28}+\frac{10}{28}=\frac{31}{28}=1\frac{3}{28}\).
6. \(\frac{9}{20}-\frac{7}{30}=\frac{27}{60}-\frac{14}{60}=\frac{13}{60}\).

Ответ: 1) \(\frac{29}{36}\); 2) \(\frac{13}{40}\); 3) \(1\frac{5}{24}\); 4) \(\frac{19}{60}\); 5) \(1\frac{3}{28}\); 6) \(\frac{13}{60}\).