Вычисли устно и запиши результат

а) \(\dfrac{1}{2} \cdot \dfrac{3}{5} = \) [ ],

\(\dfrac{1}{3} \cdot \dfrac{7}{8} = \) [ ],

\(\dfrac{1}{4} \cdot \dfrac{5}{2} = \) [ ];

б) \(\dfrac{3}{7} \cdot \dfrac{2}{5} = \) [ ],

\(\dfrac{7}{9} \cdot \dfrac{4}{5} = \) [ ],

\(\dfrac{4}{7} \cdot \dfrac{2}{11} = \) [ ];

в) \(\dfrac{5}{3} \cdot \dfrac{7}{6} = \) [ ],

\(\dfrac{3}{4} \cdot \dfrac{15}{4} = \) [ ],

\(\dfrac{6}{5} \cdot \dfrac{7}{13} = \) [ ].