\[ \begin{align*} \dfrac{9}{14} \times \dfrac{28}{27} \times 6 &= \dfrac{9\times 28\times 6}{14\times 27\times 1} \\ &= \dfrac{1512}{378} \\ &= 4 \end{align*} \] \[ \begin{align*} \dfrac{4}{15} \times \dfrac{45}{8} \times \dfrac{2}{3} &= \dfrac{4\times 45\times 2}{15\times 8\times 3} \\ &= \dfrac{360}{360} \\ &= 1 \end{align*} \] \[ \begin{align*} \dfrac{18}{25} \times \dfrac{10}{9} \times \dfrac{5}{12} &= \dfrac{18\times 10\times 5}{25\times 9\times 12} \\ &= \dfrac{900}{2700} \\ &= \dfrac{1}{3} \end{align*} \] \[ \begin{align*} 7 \times \dfrac{8}{21} \times \dfrac{3}{4} &= \dfrac{7\times 8\times 3}{1\times 21\times 4} \\ &= \dfrac{168}{84} \\ &= 2 \end{align*} \]