$\begin{array}{l}
+ )\,\,1\frac{1}{2} + 1\frac{1}{4} = \frac{3}{2} + \frac{5}{4} = \frac{6}{4} + \frac{5}{4} = \frac{{11}}{4};\\
+ )\,\,1\frac{1}{2} - 1\frac{1}{4} = \frac{3}{2} + \frac{5}{4} = \frac{6}{4} - \frac{5}{4} = \frac{1}{4};\\
+ )\,\,1\frac{1}{2} + 1\frac{1}{4} = \frac{3}{2} \times \frac{5}{4} = \frac{{15}}{8};\\
+ )\,\,1\frac{1}{2}:1\frac{1}{4} = \frac{3}{2}:\frac{5}{4} = \frac{3}{2} \times \frac{4}{5} = \frac{{12}}{{10}} = \frac{6}{5}.
\end{array}$
