To decide which is greater we have to make common denominator, for example by multiplying numerator and denominator by the same number in one fraction. Then we can look only on numerator and decide easily.
[tex] \frac{2}{3}= \frac{2*3}{3*3}= \frac{6}{9} [/tex]
[tex] \frac{6}{9} < \frac{7}{9} [/tex] - its the result
