1) Вычислите: а) \(\frac{5}{9}-\frac{4}{9}\); б) \(2\frac{4}{15}+\frac{1}{5}\); в) \(3\frac{5}{27}\cdot\frac{18}{35}\); г) \(4\frac{14}{27}:\frac{28}{81}\).

1. \(\frac{5}{9}-\frac{4}{9}=\frac{1}{9}\).
2. \(2\frac{4}{15}+\frac{1}{5}=2\frac{4}{15}+\frac{3}{15}=2\frac{7}{15}\).
3. \(3\frac{5}{27}\cdot\frac{18}{35}=\frac{86}{27}\cdot\frac{18}{35}=\frac{172}{105}=1\frac{67}{105}\).
4. \(4\frac{14}{27}:\frac{28}{81}=\frac{122}{27}\cdot\frac{81}{28}=\frac{366}{28}=13\frac{1}{14}\).

Ответ: \(\frac{1}{9};\ 2\frac{7}{15};\ 1\frac{67}{105};\ 13\frac{1}{14}\).