\[\boxed{\text{6.54.}}\]
\[\textbf{а)}\ 2\ 003\ :10 = \frac{2\ 003}{10} = 200,3;\ \]
\[\textbf{б)}\ 29\ :1\ 000 = \frac{29}{1\ 000} = 0,029;\ \]
\[\textbf{в)}\ 5\ :100 = \frac{5}{100} = 0,05;\ \]
\[\textbf{г)}\ 13\ 590\ :1\ 000 = \frac{13\ 590}{1\ 000} =\]
\[= 13,59;\ \]
\[\textbf{д)}\ 3\ 806\ :100 = \frac{3\ 806}{100} = 38,06.\ \ \ \]