Вычисли

а) \(\cfrac{1}{3}\cdot \cfrac{3}{4}=\cfrac{1\cdot \overset{\tiny 1}{\cancel{3}}}{\underset{\tiny 1}{\cancel{3}}\cdot 4}=\cfrac{1\cdot 1}{1\cdot 4}=\cfrac{1}{4}\) ;

б) \(\cfrac{12}{13}\cdot \cfrac{3}{8}=\cfrac{\overset{\tiny 3} {\cancel{12}\cdot 3}}{13\cdot \underset{\tiny 2} {\cancel{8}}}=\) [ ] \(=\) [ ];

в) \(\cfrac{5}{6}\cdot \cfrac{9}{11}=\) [ ] \(=\) [ ] \(=\) [ ];

г) \(\cfrac{5}{4}\cdot \cfrac{7}{10}=\) [ ] \(=\) [ ] \(=\) [ ];

д) \(\cfrac{6}{7}\cdot \cfrac{14}{11}=\) [ ] \(=\) [ ] \(=\) [ ];

е) \(\cfrac{51}{61}\cdot \cfrac{5}{17}=\) [ ] \(=\) [ ] \(=\) [ ].