Вычислите: 8/5 : 16/25 - 7 1/4 + 2 5/8 * 10/7. Запишите полностью решение и ответ.

13. $\frac{8}{5} : \frac{16}{25} - 7\frac{1}{4} + 2\frac{5}{8} \cdot \frac{10}{7} = \frac{8}{5} \cdot \frac{25}{16} - \frac{29}{4} + \frac{21}{8} \cdot \frac{10}{7} = \frac{1 \cdot 5}{1 \cdot 2} - \frac{29}{4} + \frac{3 \cdot 5}{4 \cdot 1} = \frac{5}{2} - \frac{29}{4} + \frac{15}{4} = \frac{10}{4} - \frac{29}{4} + \frac{15}{4} = \frac{10 - 29 + 15}{4} = -\frac{4}{4} = -1$ **Ответ: -1** 14. $\frac{25}{54} : (\frac{7}{12} - \frac{13}{18}) + 2 \cdot 2\frac{2}{3} = \frac{25}{54} : (\frac{21 - 26}{36}) + 2 \cdot \frac{8}{3} = \frac{25}{54} : (-\frac{5}{36}) + \frac{16}{3} = -\frac{25}{54} \cdot \frac{36}{5} + \frac{16}{3} = -\frac{5 \cdot 2}{3 \cdot 1} + \frac{16}{3} = -\frac{10}{3} + \frac{16}{3} = \frac{6}{3} = 2$ **Ответ: 2** 15. $-2 + (\frac{11}{24} + \frac{5}{6}) : 1\frac{15}{16} - \frac{2}{5} = -2 + (\frac{11 + 20}{24}) : \frac{31}{16} - \frac{2}{5} = -2 + \frac{31}{24} \cdot \frac{16}{31} - \frac{2}{5} = -2 + \frac{2}{3} - \frac{2}{5} = -\frac{30}{15} + \frac{10}{15} - \frac{6}{15} = \frac{-30 + 10 - 6}{15} = -\frac{26}{15} = -1\frac{11}{15}$ **Ответ: -1\frac{11}{15}**