Решение:
а) $-\frac{1}{3} * 2 = -\frac{1 * 2}{3} = -\frac{2}{3};$
б) 7 * $(-\frac{1}{2}) = -\frac{7 * 1}{2} = -\frac{7}{2} = -3\frac{1}{2};$
в) −4 * $(-\frac{1}{6}) = -\frac{-4 * 1}{6} = \frac{\overset{2}{\cancel{4}}}{\underset{3}{\cancel{6}}} = \frac{2}{3};$
г) $\frac{3}{4} * (-8) = \frac{3 * \overset{-2}{\cancel{(-8)}}}{\underset{1}{\cancel{4}}} = \frac{3 * (-2)}{1} = \frac{-6}{1} = -6;$
д) $\frac{25}{28} * (-14) = \frac{25 * \overset{-1}{\cancel{(-14)}}}{\underset{2}{\cancel{28}}} = -\frac{25 * 1}{2} = -\frac{25}{2} = -12\frac{1}{2};$
е) $-12 * (-\frac{13}{24}) = -\frac{\overset{-1}{\cancel{-12}} * 13}{\underset{2}{\cancel{24}}} = \frac{1 * 13}{2} = 6\frac{1}{2}.$
Ответ:
а) $-\frac{2}{3};$
б) $-3\frac{1}{2};$
в) $\frac{2}{3};$
г) $-6;$
д) $-12\frac{1}{2};$
е) $6\frac{1}{2}.$