[tex]\stackrel{mixed}{2\frac{3}{4}}\implies \cfrac{2\cdot 4+3}{4}\implies \stackrel{improper}{\cfrac{11}{4}} \\\\\\ 6\cdot 2\frac{3}{4}\implies \cfrac{6}{1}\cdot \cfrac{11}{4}\implies \cfrac{66}{4}\implies \cfrac{33}{2}\implies {\LARGE \begin{array}{llll} 16\frac{1}{2} \end{array}} \\\\[-0.35em] ~\dotfill[/tex]
[tex]\stackrel{mixed}{3\frac{1}{3}}\implies \cfrac{3\cdot 3+1}{3}\implies \stackrel{improper}{\cfrac{10}{3}} ~\hfill \stackrel{mixed}{3\frac{2}{5}}\implies \cfrac{3\cdot 5+2}{5}\implies \stackrel{improper}{\cfrac{17}{5}} \\\\\\ -3\frac{1}{3}\cdot -3\frac{2}{5}\implies -\cfrac{10}{3}\cdot -\cfrac{17}{5}\implies +\cfrac{170}{15}\implies \cfrac{34}{3}\implies {\LARGE \begin{array}{llll} 11\frac{1}{3} \end{array}} \\\\[-0.35em] ~\dotfill[/tex]
[tex]\stackrel{mixed}{4\frac{1}{2}}\implies \cfrac{4\cdot 2+1}{2}\implies \stackrel{improper}{\cfrac{9}{2}} ~\hfill \stackrel{mixed}{8\frac{2}{3}}\implies \cfrac{8\cdot 3+2}{3}\implies \stackrel{improper}{\cfrac{26}{3}} \\\\\\ -4\frac{1}{2}\cdot 8\frac{2}{3}\implies -\cfrac{9}{2}\cdot \cfrac{26}{3}\implies -\cfrac{234}{6}\implies \cfrac{-39}{1}\implies \text{\LARGE -39} \\\\[-0.35em] ~\dotfill[/tex]
[tex]\stackrel{mixed}{1\frac{5}{6}}\implies \cfrac{1\cdot 6+5}{6}\implies \stackrel{improper}{\cfrac{11}{6}} \\\\\\ 1\frac{5}{6}\cdot (-9)\implies \cfrac{11}{6}\cdot \cfrac{(-9)}{1}\implies -\cfrac{99}{6}\implies -\cfrac{33}{2}\implies \LARGE \begin{array}{llll} -16\frac{1}{2} \end{array}[/tex]