Ответ:
\(7\frac{5}{6}-3\frac{2}{3}=7\frac{5}{6}-3\frac{4}{6}=4\frac{1}{6}\).
Общий знаменатель дробей — \(60\): \(\frac{5}{12}=\frac{25}{60}\), \(\frac{7}{20}=\frac{21}{60}\).
\(8\frac{5}{12}-6\frac{7}{20}=2+\frac{25-21}{60}=2\frac{1}{15}\).
Общий знаменатель дробей — \(36\): \(\frac{11}{12}=\frac{33}{36}\), \(\frac{7}{9}=\frac{28}{36}\).
\(11\frac{11}{12}-5\frac{7}{9}=6+\frac{33-28}{36}=6\frac{5}{36}\).
Общий знаменатель дробей — \(72\): \(\frac{17}{24}=\frac{51}{72}\), \(\frac{11}{36}=\frac{22}{72}\).
\(9\frac{17}{24}-8\frac{11}{36}=1+\frac{51-22}{72}=1\frac{29}{72}\).
Ответ: 1) \(4\frac{1}{6}\); 2) \(2\frac{1}{15}\); 3) \(6\frac{5}{36}\); 4) \(1\frac{29}{72}\).
