\[\boxed{\text{Проверьте\ себя}\text{.\ Страница\ 57}}\]
\[\boxed{\text{Проверочная\ работа}\text{.\ Основное\ свойство\ дроби}}\]
\[\boxed{\text{1.}}\]
\[\ 7\ :23 = \frac{7}{23}\text{.\ \ \ }\]
\[\boxed{\text{2.}}\]
\[15\ :25 = \frac{15}{25}\text{.\ \ \ }\]
\[\boxed{\text{3.}}\]
\[2\frac{1}{3} = \frac{3 \cdot 2 + 1}{3} = \frac{7}{3}\text{.\ \ \ }\]
\[\boxed{\text{4.}}\]
\[\frac{15}{7} = 2\frac{1}{7}\text{.\ \ \ }\]
\[\boxed{\text{5.}}\]
\[\frac{6}{16} = \frac{3}{8}:\ \ \]
\[\frac{3}{8} = \frac{3 \cdot 2}{8 \cdot 2} = \frac{6}{16}\text{.\ \ \ }\]
\[\boxed{\text{6.}}\]
\[\frac{3}{4} = \frac{3 \cdot 2}{4 \cdot 2} = \frac{6}{8}\text{.\ \ \ }\]
\[\boxed{\text{7.}}\]
\[Да.\]
\[\ \frac{2}{3} = \frac{2 \cdot 5}{3 \cdot 5} = \frac{10}{15}\text{.\ \ \ }\]
\[\boxed{\text{8.}}\]
\[Нет.\]
\[\frac{1}{4} = \frac{1 \cdot 5}{4 \cdot 5} = \frac{5}{20}\text{.\ \ \ }\]