\[\boxed{\mathbf{2.}\mathbf{225}}\]
\[1 = 6\ клеток;\ \ \ \frac{a}{b} = \frac{4}{6}.\]
\[\textbf{а)}\ 1 - \frac{a}{b}\]
\[A = 1 - \frac{4}{6} = \frac{2}{6}.\]
\[\textbf{б)}\ 2 + \frac{a}{b}\ \]
\[B = 2 + \frac{4}{6} = 2\frac{4}{6}.\]
\[\textbf{в)}\ 3 - \frac{a}{b}\]
\[C = 3 - \frac{4}{6} = 2\frac{2}{6}.\]
\[\textbf{г)}\ 1 + 1\frac{a}{b}\ \]
\[D = 1 + 1\frac{4}{6} = 2\frac{4}{6}\]