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МатематикаРешебник по математике 5 класс Ерина Виленкин рабочая тетрадь Часть 1, 2 Часть 2 | Страница 51
Страница 51
\[Стр.\ 51.\]
\[\boxed{\mathbf{5.}}\]
\[неправильных;умножения.\]
\[\boxed{\mathbf{6.}}\]
\[\textbf{а)}\ 1\frac{3}{7} \cdot 1\frac{1}{4} = \frac{10}{7} \cdot \frac{5}{4} = \frac{10 \cdot 5}{7 \cdot 4} =\]
\[= \frac{25}{14} = 1\frac{11}{14}\]
\[\textbf{б)}\ 3\frac{1}{5} \cdot \frac{3}{8} = \frac{16}{5} \cdot \frac{3}{8} = \frac{16 \cdot 3}{5 \cdot 8} = \frac{6}{5} =\]
\[= 1\frac{1}{5}\]
\[\textbf{в)}\ 9 \cdot 4\frac{1}{6} = 9 \cdot \frac{25}{6} = \frac{9 \cdot 25}{6} =\]
\[= \frac{75}{2} = 37\frac{1}{2}\]
\[\textbf{г)}\ 3\frac{17}{21} \cdot 3\frac{1}{8} = \frac{80}{21} \cdot \frac{25}{8} =\]
\[= \frac{80 \cdot 25}{21 \cdot 8} = \frac{250}{21} = 11\frac{19}{21}\]
\[\textbf{д)}\ 16\frac{2}{3} \cdot 1\frac{1}{6} = \frac{50}{3} \cdot \frac{7}{6} = \frac{25 \cdot 7}{9} =\]
\[= \frac{175}{9} = 19\frac{4}{9}\]
\[2\frac{3}{4} \cdot 3\frac{1}{3} = \frac{11}{4} \cdot \frac{10}{3} = \frac{55}{6} = 9\frac{1}{6}\]
\[\textbf{е)}\ 5\frac{2}{5} \cdot 3\frac{1}{3} = \frac{27}{5} \cdot \frac{10}{3} = 9 \cdot 2 =\]
\[= 18\]
\[3\frac{1}{3} \cdot 3\frac{3}{5} = \frac{10}{3} \cdot \frac{18}{5} = 2 \cdot 6 = 12\]
\[\textbf{ж)}\ 1\frac{2}{7} \cdot 1\frac{1}{4} = \frac{9}{7} \cdot \frac{5}{4} = \frac{45}{28} = 1\frac{17}{28}\]
\[6\frac{1}{2} \cdot 1\frac{1}{39} = \frac{13}{2} \cdot \frac{40}{39} = \frac{20}{3} = 6\frac{2}{3}\]
\[\textbf{з)}\ 33\frac{1}{3} \cdot 1\frac{1}{5} = \frac{100}{3} \cdot \frac{6}{5} = 20 \cdot 2 =\]
\[= 40\]
\[2\frac{4}{5} \cdot 6\frac{3}{7} = \frac{14}{5} \cdot \frac{45}{7} = 2 \cdot 9 = 18\]
\[\textbf{и)}\ 2\frac{2}{5} \cdot 13\frac{1}{3} = \frac{12}{5} \cdot \frac{40}{3} = 4 \cdot 8 =\]
\[= 32\]
\[3\frac{1}{16} \cdot 1\frac{5}{7} = \frac{49}{16} \cdot \frac{12}{7} = \frac{7 \cdot 3}{4 \cdot 1} =\]
\[= \frac{21}{4} = 5\frac{1}{4}\]
\[к)\ 5\frac{3}{4} \cdot 1\frac{1}{7} = \frac{23}{4} \cdot \frac{8}{7} = \frac{46}{7} = 6\frac{5}{7}\]
\[3\frac{7}{9} \cdot 1\frac{1}{17} = \frac{34}{9} \cdot \frac{18}{17} = 2 \cdot 2 = 4\]
