Реши 2 и 3 столбик

- в) $\frac{3}{10} - \frac{4}{15} = \frac{9}{30} - \frac{8}{30} = \frac{1}{30}$ - г) $5 - 3\frac{2}{7} = 4\frac{7}{7} - 3\frac{2}{7} = 1\frac{5}{7}$ - д) $\frac{4}{9} \cdot \frac{3}{8} = \frac{4 \cdot 3}{9 \cdot 8} = \frac{12}{72} = \frac{1}{6}$ - e) $\frac{5}{8} : \frac{9}{10} = \frac{5}{8} \cdot \frac{10}{9} = \frac{5 \cdot 10}{8 \cdot 9} = \frac{50}{72} = \frac{25}{36}$ - ж) $2\frac{6}{7} \cdot 6\frac{3}{5} = \frac{20}{7} \cdot \frac{33}{5} = \frac{20 \cdot 33}{7 \cdot 5} = \frac{660}{35} = \frac{132}{7} = 18\frac{6}{7}$ **Второй столбик:** - г) $1,2 \cdot (-5) = -6$ - д) $-8 \cdot 4,5 = -36$ - е) $-0,9 \cdot (-0,1) = 0,09$ - ж) $38 : (-0,1) = -380$ - з) $-16 : 0,2 = -80$ - и) $-6,4 : (-8) = 0,8$ **Третий столбик:** - г) $\frac{3}{8} : (-\frac{9}{16}) = \frac{3}{8} \cdot (-\frac{16}{9}) = -\frac{3 \cdot 16}{8 \cdot 9} = -\frac{48}{72} = -\frac{2}{3}$ - ж) $\frac{4}{7} \cdot (-49) = -\frac{4 \cdot 49}{7} = -\frac{196}{7} = -28$ - д) $\frac{5}{12} \cdot (-6) = -\frac{5 \cdot 6}{12} = -\frac{30}{12} = -\frac{5}{2} = -2\frac{1}{2}$ - з) $-16 : (-\frac{4}{9}) = -16 \cdot (-\frac{9}{4}) = \frac{16 \cdot 9}{4} = \frac{144}{4} = 36$ - e) $-3\frac{2}{9} \cdot 3 = -\frac{29}{9} \cdot 3 = -\frac{29 \cdot 3}{9} = -\frac{87}{9} = -\frac{29}{3} = -9\frac{2}{3}$ - и) $-3\frac{1}{2} \cdot (-1\frac{3}{7}) = -\frac{7}{2} \cdot (-\frac{10}{7}) = \frac{7 \cdot 10}{2 \cdot 7} = \frac{70}{14} = 5$