\[\boxed{\mathbf{2.}\mathbf{224}}\]
\[3\frac{1}{4} = 3\frac{3}{12}\]
\[3\frac{3}{12} < A < 4\frac{5}{12}\]
\[A = \{ 3\frac{4}{12};3\frac{5}{12};3\frac{6}{12};3\frac{7}{12};\]
\[3\frac{8}{12};3\frac{9}{12};3\frac{10}{12};3\frac{11}{12};3\frac{12}{12};\]
\[4\frac{1}{12};4\frac{2}{12};4\frac{3}{12};4\frac{4}{12}\}.\ \]