[tex](4 \frac{1}{7} - 2 \frac{3}{4} ) \times ( \frac{1}{3} + \frac{8}{39} ) = \\ \\ (\frac{29}{7} - \frac{11}{4} ) \times \frac{13 + 8}{39} = \\ \\ \frac{116 - 77}{28} \times \frac{21}{39} = \\ \\ \frac{39}{28} \times \frac{21}{39} = \\ \\ \frac{3}{4} = 0.75[/tex]
