\[\boxed{\text{5.19.}}\]
\[\textbf{а)}\ 1\ кг\ :100 = 1\ 000\ г\ :100 =\]
\[= 10\ г\]
\[\textbf{б)}\ 1\ ц\ :10 = 100\ 000\ г\ :10 =\]
\[= 10\ 000\ г\]
\[\textbf{в)}\ 1\ кг\ :25 = 1\ 000\ г\ :25 =\]
\[= 40\ г\]
\[\textbf{г)}\ 1\ ц\ :4 = 100\ 000\ г\ :4 =\]
\[= 25\ 000\ г\ \]
\[\textbf{д)}\ 1\ т\ :1\ 000 =\]
\[= 1\ 000\ 000\ г\ :1\ 000 =\]
\[= 1\ 000\ г\ \]
\[\textbf{е)}\ 1\ т\ :40 = 1\ 000\ 000\ г\ :40 =\]
\[= 25\ 000\ г\ \]