\[Стр.\ 61.\]
\[\boxed{\mathbf{4.}}\]
\[\frac{2}{5};\ \ \frac{7}{8};\ \ \frac{21}{40};\ \ \frac{7}{20};\ \ \frac{7}{27};\ \ \frac{17}{45}.\]
\[\boxed{\mathbf{5.}}\]
\[\frac{2}{15} = 0,1(33);\]
\[\textbf{а)}\ 0,1;0,2;\ \ \]
\[\ б)\ 0,13;0,14;\ \ \ \]
\[\textbf{в)}\ 0,133;\ 0,134\]