[tex]\dfrac{7}{9} -\dfrac{2}{9} =\boxed{\dfrac{5}{9} }[/tex]
[tex]1\dfrac{5}{12} -\dfrac{1}{12} =1\dfrac{4}{12} =\boxed{1\dfrac{1}{3} }[/tex]
[tex]4\dfrac{2}{5} -3=\boxed{1\dfrac{2}{5} }[/tex]
[tex]6\dfrac{6}{7} -2\dfrac{4}{7} =\boxed{4\dfrac{2}{7} }[/tex]
