83. Выполните действие: а) \(7\frac{5}{12}+4\frac{3}{8}\); б) \(3\frac{11}{20}+2\frac{19}{30}\); в) \(9\frac{5}{6}-2\frac{3}{4}\); г) \(3\frac{3}{10}-1\frac{7}{15}\).

1. \[7\frac{5}{12}+4\frac{3}{8}=11+\frac{10}{24}+\frac{9}{24}=11\frac{19}{24}.\]
2. \[3\frac{11}{20}+2\frac{19}{30}=5+\frac{33}{60}+\frac{38}{60}=6\frac{11}{60}.\]
3. \[9\frac{5}{6}-2\frac{3}{4}=7+\frac{10}{12}-\frac{9}{12}=7\frac{1}{12}.\]
4. \[3\frac{3}{10}-1\frac{7}{15}=3\frac{9}{30}-1\frac{14}{30}=1\frac{25}{30}=1\frac{5}{6}.\]

Ответ: а) \(11\frac{19}{24}\); б) \(6\frac{11}{60}\); в) \(7\frac{1}{12}\); г) \(1\frac{5}{6}\).