РЕШИТЕ СРОЧНО НОМЕР 823 824 825

823
а) $\frac{1}{3} * \frac{2}{7} = \frac{1*2}{3*7} = \frac{2}{21}$
б) $\frac{1}{2} * \frac{5}{6} = \frac{5}{12}$
в) $\frac{3}{4} * \frac{1}{4} = \frac{3}{16}$
824
а) $\frac{8}{9} * \frac{3}{5} = \frac{8*3}{9*5} = \frac{8*1}{3*5} = \frac{8}{15}$
б) $\frac{9}{2} * \frac{2}{9} = \frac{9*2}{2*9} = \frac{1*1}{1*1} = 1$
в) $\frac{8}{21} * \frac{7}{10} = \frac{8*7}{21*10} = \frac{4*1}{3*5} = \frac{4}{15}$
825
а) $\frac{3}{7} * 2 = \frac{6}{7}$
б) $3 * \frac{1}{6} = 1 * \frac{1}{2} = \frac{1}{2}$
в) $9 * \frac{5}{6} = 3 * \frac{5}{2} = \frac{15}{2}$
г) $\frac{2}{5}* 15 = \frac{2}{1} * 3 = 6$
д) $\frac{1}{4}* 4 =\frac{1}{1} *1= 1$
е) $5*\frac{1}{5}= 1 *\frac{1}{1} = 1$