9) 7 4/9 - 3 5/9 =

9) $$\begin{aligned}7\frac{4}{9} - 3\frac{5}{9} &= 6 + \frac{9}{9} + \frac{4}{9} - 3\frac{5}{9} = 6 + \frac{13}{9} - 3 - \frac{5}{9} = 3\frac{8}{9}\\\\&=\frac{3 \cdot 9 + 8}{9} = \frac{27+8}{9} = \frac{35}{9} = 3\frac{8}{9}\end{aligned}$$

Ответ: 3 8/9