Ответ:
\(\frac{1}{3}+\frac{2}{9}=\frac{3}{9}+\frac{2}{9}=\frac{5}{9}\).
\(\frac{9}{10}:\frac{5}{9}=\frac{9}{10}\cdot\frac{9}{5}=\frac{81}{50}\).
Ответ: \(\frac{81}{50}\).
\(\frac{1}{3}+\frac{2}{9}=\frac{3}{9}+\frac{2}{9}=\frac{5}{9}\).
\(\frac{9}{10}:\frac{5}{9}=\frac{9}{10}\cdot\frac{9}{5}=\frac{81}{50}\).
Ответ: \(\frac{81}{50}\).