\[6\frac{5}{12} - \left( - 4\frac{2}{3} \right) + \left( - 2\frac{3}{4} \right) =\]
\[= 6\frac{5}{12} + 4\frac{8}{12} - 2\frac{9}{12} =\]
\[= 10\frac{13}{12} - 2\frac{9}{12} = 8\frac{4}{12} = 8\frac{1}{3}\]