ГДЗ по математике 5 класс Ткачева рабочая тетрадь | Страница 67

\[\boxed{\mathbf{2.}}\]

\[1)\ \frac{8}{13} \cdot \frac{39}{28} = \frac{8 \cdot 39}{13 \cdot 28} = \frac{2 \cdot 3}{1 \cdot 7} = \frac{6}{7}\]

\[2)\ \frac{12}{55} \cdot \frac{77}{160} = \frac{12 \cdot 77}{55 \cdot 160} = \frac{3 \cdot 7}{5 \cdot 40} =\]

\[= \frac{21}{200}\]

\[\boxed{\mathbf{3.}}\]

\[1)\ 2\frac{2}{5} \cdot 1\frac{2}{3} = \frac{12}{5} \cdot \frac{5}{3} = \frac{12 \cdot 5}{5 \cdot 3} =\]

\[= 4 \cdot 1 = 4\]

\[2)\ повтор\ 1).\]

\[3)\ 1\frac{4}{7} \cdot 2\frac{5}{22} = \frac{11}{7} \cdot \frac{49}{22} =\]

\[= \frac{11 \cdot 49}{7 \cdot 22} = \frac{1 \cdot 7}{1 \cdot 2} = \frac{7}{2} = 3\frac{1}{2}\]

\[\boxed{\mathbf{4.}}\]

\[1)\ \frac{2}{9}\ от\ \ 6\frac{3}{4}:\]

\[6\frac{3}{4} \cdot \frac{2}{9} = \frac{27}{4} \cdot \frac{2}{9} = \frac{27 \cdot 2}{4 \cdot 9} =\]

\[= \frac{3 \cdot 1}{2 \cdot 1} = \frac{3}{2} = 1\frac{1}{2}.\]

\[2)\ \frac{6}{7}\ \ от\ \ 1\frac{17}{18}:\]

\[1\frac{17}{18} \cdot \frac{6}{7} = \frac{35}{18} \cdot \frac{6}{7} = \frac{35 \cdot 6}{18 \cdot 7} =\]

\[= \frac{5 \cdot 1}{3 \cdot 1} = \frac{5}{3} = 1\frac{2}{3}.\]

\[\mathbf{40.\ Деление\ дробей}\]

\[\boxed{\mathbf{1.}}\]

\[1)\ \frac{1}{4} \rightarrow \frac{4}{1} = 4\]

\[2)\ \frac{2}{7} \rightarrow \frac{7}{2} = 3\frac{1}{2}\]

\[3)\ 3 = \frac{3}{1} \rightarrow \frac{1}{3}\]

\[4)\ 3\frac{1}{6} = \frac{19}{6} \rightarrow \frac{6}{19}\]