Question

Вариант 3.
1. *Найдите произведение:
а) 3/7×5/11=
б) 6/25×5/18=
в) 2 1/10×1 1/14=
г) 3 3/5×1 1/9=
д) 1 3/7×14=
​

Answer 1

Пошаговое объяснение:

а)

$\frac{3}{7} \times \frac{5}{11} = \frac{3 \times 5}{7 \times 11} = \frac{15}{77}$

б)

$\frac{6}{25} \times \frac{5}{18} = \frac{6 \times 5}{25 \times 18} = \frac{30}{450} = \frac{1}{15}$

в)

$2 \frac{1}{10} \times 1 \frac{1}{14} =\frac{20+1}{10}\times \left(\frac{1\times 14+1}{14}\right) =\frac{21}{10}\times \left(\frac{1\times 14+1}{14}\right) =\frac{21}{10}\times \left(\frac{14+1}{14}\right) =\frac{21}{10}\times \left(\frac{15}{14}\right) =\frac{21\times 15}{10\times 14} =\frac{315}{140} =\frac{9}{4} =2\frac{1}{4} = 2.25$

г)

$3 \frac{3}{5} \times 1\frac{1}{9} = \frac{15 + 3}{5} \times ( \frac{1 \times 9 + 1}{9} ) = \frac{18}{5} \times (\frac{1 \times 9 + 1}{9} ) = \frac{18}{5}\times \left(\frac{9+1}{9}\right) =\frac{18}{5}\times \left(\frac{10}{9}\right) =\frac{18\times 10}{5\times 9} =\frac{180}{45} =4$

д)

$1 \frac{3}{7} \times 14 = \frac{7 + 3}{7} \times 14 = \frac{10}{7} \times 14 = \frac{10 \times 14}{7} = \frac{140}{7} = 20$