Вычисли значения выражений в задании 19 а)

- a) $6\frac{1}{3} - 8 = \frac{19}{3} - 8 = \frac{19}{3} - \frac{24}{3} = -\frac{5}{3} = -1\frac{2}{3}$ - б) $-2\frac{2}{7} + 4\frac{3}{5} = -\frac{16}{7} + \frac{23}{5} = -\frac{16 \cdot 5}{7 \cdot 5} + \frac{23 \cdot 7}{5 \cdot 7} = -\frac{80}{35} + \frac{161}{35} = \frac{81}{35} = 2\frac{11}{35}$ - в) $5\frac{1}{3} - 6\frac{1}{4} = \frac{16}{3} - \frac{25}{4} = \frac{16 \cdot 4}{3 \cdot 4} - \frac{25 \cdot 3}{4 \cdot 3} = \frac{64}{12} - \frac{75}{12} = -\frac{11}{12}$ - г) $\frac{3}{8} : (-\frac{9}{16}) = \frac{3}{8} \cdot (-\frac{16}{9}) = -\frac{3 \cdot 16}{8 \cdot 9} = -\frac{48}{72} = -\frac{2}{3}$ - д) $\frac{5}{12} \cdot (-6) = -\frac{5 \cdot 6}{12} = -\frac{30}{12} = -\frac{5}{2} = -2\frac{1}{2}$ - e) $-3\frac{2}{9} \cdot 3 = -\frac{29}{9} \cdot 3 = -\frac{29 \cdot 3}{9} = -\frac{29}{3} = -9\frac{2}{3}$ - ж) $\frac{4}{7} \cdot (-49) = -\frac{4 \cdot 49}{7} = -4 \cdot 7 = -28$ - з) $-16 : (-\frac{4}{9}) = 16 \cdot \frac{9}{4} = \frac{16 \cdot 9}{4} = 4 \cdot 9 = 36$ - и) $-3\frac{1}{2} \cdot (-1\frac{3}{7}) = -\frac{7}{2} \cdot (-\frac{10}{7}) = \frac{7 \cdot 10}{2 \cdot 7} = \frac{10}{2} = 5$ **Ответы:** - a) $-1\frac{2}{3}$ - б) $2\frac{11}{35}$ - в) $-\frac{11}{12}$ - г) $-\frac{2}{3}$ - д) $-2\frac{1}{2}$ - e) $-9\frac{2}{3}$ - ж) $-28$ - з) $36$ - и) $5$