Ответ:

  1. а) \(7-4\frac{5}{9}=6\frac{9}{9}-4\frac{5}{9}=2\frac{4}{9}\).
  2. б) \(4\frac{3}{10}+1\frac{5}{12}=5+\frac{36}{120}+\frac{50}{120}=5\frac{86}{120}=5\frac{43}{60}\).
  3. в) \(6\frac{13}{21}+2\frac{9}{14}=8+\frac{26}{42}+\frac{27}{42}=8\frac{53}{42}=9\frac{11}{42}\).
  4. г) \(5\frac{1}{6}-3\frac{3}{4}=\frac{31}{6}-\frac{15}{4}=\frac{62}{12}-\frac{45}{12}=\frac{17}{12}=1\frac{5}{12}\).

Ответ: а) \(2\frac{4}{9}\); б) \(5\frac{43}{60}\); в) \(9\frac{11}{42}\); г) \(1\frac{5}{12}\).