5. Вычислите: 1) 9/12 + 3/12; 2) 7 − 4 32/54; 3) 15 23/28 − 11 24/28.

1) \(\frac{9}{12}+\frac{3}{12}=\frac{12}{12}=1\).

2) \(7-4\frac{32}{54}=6\frac{54}{54}-4\frac{32}{54}=2\frac{22}{54}=2\frac{11}{27}\).

3) \(15\frac{23}{28}-11\frac{24}{28}=14\frac{51}{28}-11\frac{24}{28}=3\frac{27}{28}\).

Ответ: 1) 1; 2) \(2\frac{11}{27}\); 3) \(3\frac{27}{28}\).