To subtract similar fractions (fractions with same denominator), simply subtract their numerator.
[tex]\frac{11}{9}-\frac{5}{9}=\frac{11-5}{9}=\frac{6}{9}[/tex]The difference of the two is 6/9 however, since 6/9 can be simplified by dividing both numerator and denominator by 3, the difference is 6/9 or 2/3.
[tex]\frac{6}{9}\div\frac{3}{3}=\frac{2}{3}[/tex]Showing this on a number line, we have:
