1. Вычислите: а) \(\frac{2}{3}+\frac{1}{9}\); б) \(\frac{3}{4}:\frac{7}{8}\); в) \(3-\frac{2}{3}\cdot\frac{3}{7}\).

1. \(\frac{2}{3}+\frac{1}{9}=\frac{6}{9}+\frac{1}{9}=\frac{7}{9}\).
2. \(\frac{3}{4}:\frac{7}{8}=\frac{3}{4}\cdot\frac{8}{7}=\frac{6}{7}\).
3. \(3-\frac{2}{3}\cdot\frac{3}{7}=3-\frac{2}{7}=\frac{21}{7}-\frac{2}{7}=\frac{19}{7}=2\frac{5}{7}\).

Ответ: а) \(\frac{7}{9}\); б) \(\frac{6}{7}\); в) \(2\frac{5}{7}\).