Вычисли

а) \(\left(\dfrac{2}{9} + \dfrac{7}{9}\right) + \left(\dfrac{4}{3} + \dfrac{2}{3}\right) = \) [ ];

б) \(\left(\dfrac{7}{8} + \dfrac{1}{8}\right) + \left(\dfrac{3}{10} + \dfrac{7}{10}\right) = \) [ ];

в) \(\dfrac{1}{4} + \dfrac{5}{12} + \dfrac{7}{12} + \dfrac{3}{4} = \) [ ];

г) \(\dfrac{14}{15} + \dfrac{3}{2} + \dfrac{16}{15} + \dfrac{1}{2} = \) [ ].