\[2\frac{3}{4} - \left( - 1\frac{1}{2} \right) + \left( - 3\frac{5}{6} \right) =\]
\[= 2\frac{3}{4} + 1\frac{1^{\backslash 2}}{2} - 3\frac{5}{6} =\]
\[= 2\frac{3}{4} + 1\frac{2}{4} - 3\frac{5}{6} =\]
\[= 3\frac{5^{\backslash 3}}{4} - 3\frac{5^{\backslash 2}}{6} =\]
\[= 3\frac{15}{12} - 3\frac{10}{12} = \frac{5}{12}.\]