5 4 -- -- = 9 27

$$\frac{5}{9} - \frac{4}{27} = \frac{5 \cdot 3}{9 \cdot 3} - \frac{4}{27} = \frac{15}{27} - \frac{4}{27} = \frac{11}{27}$$

Ответ: $$\frac{11}{27}$$