г) 27/64 : 9;

$$\frac{27}{64} : 9 = \frac{27}{64} : \frac{9}{1} = \frac{27}{64} \cdot \frac{1}{9} = \frac{27}{64 \cdot 9} = \frac{3 \cdot 9}{64 \cdot 9} = \frac{3}{64}$$