Л) \(\frac{7}{9} : 9 + \frac{5}{9} \cdot \frac{1}{9} - \frac{1}{3} \cdot \frac{1}{9}\)

Решение:

1. \(\frac{7}{9} : 9 = \frac{7}{9 \cdot 9} = \frac{7}{81}\)
2. \(\frac{5}{9} \cdot \frac{1}{9} = \frac{5}{81}\)
3. \(\frac{1}{3} \cdot \frac{1}{9} = \frac{1}{27}\)
4. \(\frac{7}{81} + \frac{5}{81} - \frac{1}{27} = \frac{7+5}{81} - \frac{1 \cdot 3}{27 \cdot 3} = \frac{12}{81} - \frac{3}{81} = \frac{12-3}{81} = \frac{9}{81} = \frac{1}{9}\)

Ответ: \(\frac{1}{9}\)