\[\boxed{\text{7.7.}}\]
\[\textbf{а)}\ 1\ :4 = \frac{1}{4} = 0,25\]
\[\textbf{б)}\ 3\ :25 = 0,12\]
\[\textbf{в)}\ 1\ :0,001 = 1000\ :1 = 1000\]
\[\textbf{г)}\ 2\ :0,25 = 200\ :25 = 8\]
\[\textbf{г)}\ 5\ :0,02 = 500\ :2 = 250\]
\[\textbf{д)}\ 4\ :1,25 = 400\ :125 = 3,2\]