1.)
[tex]7 \frac{3}{9} - 2 \frac{4}{9} \\ = \frac{66}{9} - \frac{22}{9} \\ = \frac{44}{9} \\ = 4 \frac{8}{9} [/tex]
2.)
[tex]11 \frac{3}{4} - 5 \frac{1}{4} \\ = \frac{47}{4} - \frac{21}{4} \\ = \frac{26}{4} \\ = \frac{13}{2} \\ = 6 \frac{1}{2} [/tex]
Hope it helps and is useful :)