83. Выполните действие: а) 4 1/6 + 3 2/5; б) 8 3/4 − 7 5/6; в) 2 11/12 + 6 5/8; г) 2 13/14 − 1 20/21.

1. \(4\frac{1}{6}+3\frac{2}{5}=7+\frac{5}{30}+\frac{12}{30}=7\frac{17}{30}\).
2. \(8\frac{3}{4}-7\frac{5}{6}=\frac{35}{4}-\frac{47}{6}=\frac{105-94}{12}=\frac{11}{12}\).
3. \(2\frac{11}{12}+6\frac{5}{8}=8+\frac{22}{24}+\frac{15}{24}=8\frac{37}{24}=9\frac{13}{24}\).
4. \(2\frac{13}{14}-1\frac{20}{21}=1+\frac{39}{42}-\frac{40}{42}=\frac{41}{42}\).

Ответ: а) \(7\frac{17}{30}\); б) \(\frac{11}{12}\); в) \(9\frac{13}{24}\); г) \(\frac{41}{42}\).