\[\boxed{\text{6.318.}}\]
\[\textbf{а)}\ 13,5\ :4,5 = 135\ :45 = 3\ \]
\[\textbf{б)}\ 199,26\ :0,82 = 19\ 926\ :82 =\]
\[= 243\ \]
\[\textbf{в)}\ 16,51\ :1,27 = 1651\ :127 =\]
\[= 13\ \]
\[\textbf{г)}\ 4,5\ :0,6 = 45\ :6 = 7,5\]