Question

3 3/5×2 1/12
4 2/7×2 4/5
срочно 30 баллов​

Answer 1

Пошаговое объяснение:

$3\frac{3 }{5} \times 2 \frac{1}{12} = \frac{15 + 3}{5} \times ( \frac{2 \times 12 + 1}{12} ) = \frac{18}{5} \times ( \frac{2 \times1 2 + 1}{12} ) = \frac{18}{5} \times ( \frac{24 + 1}{12} ) = \frac{18}{5} \times ( \frac{25}{12} ) = \frac{18 \times 25}{5 \times 12 } = \frac{450}{60} = \frac{15}{2} = 7 \frac{1}{2} = 7.5$

$4\frac{2}{7} \times 2 \frac{4}{5} =\frac{28+2}{7}\times \left(\frac{2\times 5+4}{5}\right) =\frac{30}{7}\times \left(\frac{2\times 5+4}{5}\right) =\frac{30}{7}\times \left(\frac{10+4}{5}\right) =\frac{30}{7}\times \left(\frac{14}{5}\right) =\frac{30\times 14}{7\times 5} =\frac{420}{35} =12$