\[ \begin{align*} \dfrac{3}{5} \times \dfrac{7}{9} &= \dfrac{3\times 7}{5\times 9} \\ &= \dfrac{21}{45} \\ &= \dfrac{7}{15} \end{align*} \] \[ \begin{align*} \dfrac{8}{11} \times \dfrac{5}{6} &= \dfrac{8\times 5}{11\times 6} \\ &= \dfrac{40}{66} \\ &= \dfrac{20}{33} \end{align*} \] \[ \begin{align*} \dfrac{2}{7} \times \dfrac{9}{4} &= \dfrac{2\times 9}{7\times 4} \\ &= \dfrac{18}{28} \\ &= \dfrac{9}{14} \end{align*} \] \[ \begin{align*} 3 \times \dfrac{5}{12} &= \dfrac{3\times 5}{1\times 12} \\ &= \dfrac{15}{12} \\ &= \dfrac{5}{4} \end{align*} \]