\[\boxed{\text{4.\ 340}}\]
\[\textbf{а)}\ 4 = \frac{4}{1};\ \ 1 = \frac{1}{1};\ \ 0 = 0;\ \]
\[- 1 = \frac{- 1}{1};\]
\[\textbf{б)}\ 0,35 = \frac{35}{100} = \frac{7}{20};\ \ \ \ \]
\[1,23 = \frac{123}{100};\ \]
\[- 3,18 = - \frac{318}{100} = \frac{- 159}{50};\ \ \ \]
\[- 1,008 = - \frac{1008}{1000} = \frac{- 126}{125}\]
\[\textbf{в)}\ \ 2\frac{5}{7} = \frac{19}{7};\ - \frac{2}{3} = \frac{- 2}{3};\ \]
\[- \frac{7}{12} = \frac{- 7}{12};\ - 3\frac{8}{9} = \frac{- 35}{8}\]