\[\boxed{\text{5.502.}}\]
\[\textbf{а)}\ 1 - \frac{1}{4} = \frac{4}{4} - \frac{1}{4} = \frac{3}{4}.\]
\[\textbf{б)}\ \frac{3}{4} - \frac{1}{4} = \frac{2}{4} = \frac{1}{2}.\]
\[\textbf{в)}\ \frac{1^{\backslash 2}}{2} - \frac{1}{4} = \frac{2}{4} - \frac{1}{4} = \frac{1}{4}.\]
\[\textbf{г)}\ \frac{1}{3} - \frac{1}{4} = \frac{4}{12} - \frac{3}{12} = \frac{1}{12}.\]