[tex]\frac{7}{9}-\frac{3}{9}=\frac{7-3}{9}=\frac{4}{9}\\\frac{9}{11}-\frac{8}{11}=\frac{1}{11}\\\frac{4}{5}-\frac{3}{4} =\frac{16-15}{20}=\frac{1}{20}\\\frac{9}{10}-\frac{1}{2}=\frac{9-5}{10}=\frac{4}{10}=\frac{2}{5}\\[/tex]
