$a)$

$\frac{3}{{\sout{4}}^2}\cdot {\sout{6}}^3=\frac{3}{2}\cdot 3=\frac{9}{2}=4\frac{1}{2}$

${\sout{3}}^1\cdot \frac{2}{{\sout{3}}^1}=\frac{2}{1}=2$