СРОЧНО СМ. ФОТО. ЗАРАНЕЕ СПАСИБО

1.
$\frac{2}{3} \times \frac{9}{14} = \frac{18}{42} = \frac{3}{7}$
2.
$\frac{4}{5} \times \frac{15}{16} = \frac{60}{80} = \frac{30}{40} = \frac{3}{4}$
3.
$\frac{3}{7} \times \frac{8}{21} = \frac{24}{147} = \frac{8}{49}$
4.
$\frac{12}{23} \times 1 = \frac{12}{23}$
5.
$\frac{17}{39} \times 0 = 0$
6.
$\frac{2}{5} \div \frac{4}{5} = \frac{2}{5} \times \frac{5}{4} = \frac{10}{20} = \frac{1}{2}$
7.
$\frac{3}{7} \div \frac{9}{14} = \frac{3}{7} \times \frac{14}{9} = \frac{42}{63} = \frac{2}{3}$
8.
$\frac{5}{8} \div \frac{1}{40} = \frac{5}{8} \times \frac{40}{1} = \frac{200}{8} = \frac{25}{1} = 25$
9.
$\frac{3}{17} \div \frac{2}{51} = \frac{3}{17} \times \frac{51}{2} = \frac{153}{34} = \frac{9}{2} = 4 \frac{1}{2}$
10.
$\frac{2}{11} \div \frac{4}{77} = \frac{2}{11} \times \frac{77}{4} = \frac{154}{44} = \frac{7}{2} = 3 \frac{1}{2}$
11.
$\frac{3}{4} \times 2 = \frac{6}{4} = 1 \frac{1}{2}$

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