5.560 Вычислите: 1) \(\frac{1}{4} \cdot \frac{1}{4} + \frac{2}{7}\); 2) \(\frac{1}{3} + \frac{7}{8} : \frac{9}{14}\); 3) \(\frac{1}{3} + \frac{7}{8} : \frac{9}{14}\); 4) \(\frac{6}{7} : \frac{5}{7} \cdot \frac{4}{9}\).

1) \(\frac{1}{4} \cdot \frac{1}{4} + \frac{2}{7} = \frac{1}{16} + \frac{2}{7} = \frac{7 + 32}{112} = \frac{39}{112}\) 2) \(\frac{1}{3} + \frac{7}{8} : \frac{9}{14} = \frac{1}{3} + \frac{7}{8} \cdot \frac{14}{9} = \frac{1}{3} + \frac{7 \cdot 7}{4 \cdot 9} = \frac{1}{3} + \frac{49}{36} = \frac{12 + 49}{36} = \frac{61}{36}\) 3) \(\frac{1}{3} + \frac{7}{8} : \frac{9}{14} = \frac{1}{3} + \frac{7}{8} \cdot \frac{14}{9} = \frac{1}{3} + \frac{7 \cdot 7}{4 \cdot 9} = \frac{1}{3} + \frac{49}{36} = \frac{12 + 49}{36} = \frac{61}{36}\) 4) \(\frac{6}{7} : \frac{5}{7} \cdot \frac{4}{9} = \frac{6}{7} \cdot \frac{7}{5} \cdot \frac{4}{9} = \frac{6 \cdot 7 \cdot 4}{7 \cdot 5 \cdot 9} = \frac{24}{45} = \frac{8}{15}\)