Решебник по математике 5 класс Ерина Виленкин рабочая тетрадь Часть 1, 2 Часть 2 | Страница 38

\[Стр.\ 38.\]

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

\[\textbf{а)}\ \frac{14}{21} = \frac{2}{3}\]

\[\frac{12}{30} = \frac{2}{5}\]

\[\frac{24}{60} = \frac{2}{5}\]

\[\frac{35}{105} = \frac{1}{3}\]

\[\textbf{б)}\ \frac{55}{77} = \frac{5}{7}\]

\[\frac{81}{270} = \frac{3}{10}\]

\[\frac{75}{450} = \frac{15}{90} = \frac{1}{6}\]

\[\frac{135}{180} = \frac{15}{20} = \frac{3}{4}\]

\[\textbf{в)}\ \frac{140}{210} = \frac{2}{3}\]

\[\frac{105}{165} = \frac{21}{33} = \frac{7}{11}\]

\[\frac{144}{360} = \frac{12}{30} = \frac{2}{5}\]

\[\frac{240}{560} = \frac{3}{7}\]

\[\textbf{г)}\ \frac{30}{150} = \frac{1}{5}\]

\[\frac{80}{200} = \frac{8}{20} = \frac{2}{5}\]

\[\frac{21}{36} = \frac{7}{12}\]

\[\frac{81}{108} = \frac{9}{12} = \frac{3}{4}\]

\[\boxed{\mathbf{5.}}\]

\[\textbf{а)}\ \frac{108}{960} = \frac{36}{320} = \frac{9}{80}\]

\[\textbf{б)}\ \frac{256}{640} = \frac{64}{160} = \frac{16}{40} = \frac{4}{10} = \frac{2}{5}\]

\[\textbf{в)}\ \frac{360}{840} = \frac{9}{21} = \frac{3}{7}\]

\[\textbf{г)}\ \frac{333}{1290} = \frac{111}{430}\]

\[\boxed{\mathbf{6.}}\]

\[\textbf{а)}\ \frac{2 \cdot 35 \cdot 18}{9 \cdot 14 \cdot 40} = \frac{2 \cdot 5 \cdot 7 \cdot 2 \cdot 9}{9 \cdot 2 \cdot 7 \cdot 5 \cdot 8} =\]

\[= \frac{2}{8} = \frac{1}{4}\]

\[\textbf{б)}\ \frac{19 \cdot 8 \cdot 5 \cdot 11}{22 \cdot 4 \cdot 20 \cdot 19} =\]

\[= \frac{19 \cdot 11 \cdot 2 \cdot 4 \cdot 5}{19 \cdot 11 \cdot 2 \cdot 4 \cdot 5 \cdot 4} = \frac{1}{4}\]

\[\textbf{в)}\ \frac{15 \cdot 13 \cdot 6}{6 \cdot 9 \cdot 5 \cdot 26} =\]

\[= \frac{5 \cdot 3 \cdot 13 \cdot 6}{6 \cdot 3 \cdot 5 \cdot 3 \cdot 13 \cdot 2} = \frac{1}{6}\]

\[\boxed{\mathbf{7.}}\]

\[720\ :36 \cdot 5 = 20 \cdot 5 = 100 -\]

\[числитель.\]

\[НОК(20;30;75) = 300 -\]

\[знаменатель.\]

\[\frac{100}{300} = \frac{1}{3}.\]

\[Ответ:\frac{1}{3}.\]