let's firstly convert the mixed fractions to improper fractions and then subtract.
[tex]\bf \stackrel{mixed}{7\frac{1}{3}}\implies \cfrac{7\cdot 3+1}{3}\implies \stackrel{improper}{\cfrac{22}{3}}~\hfill \stackrel{mixed}{2\frac{1}{2}}\implies \cfrac{2\cdot 2+1}{2}\implies \stackrel{improper}{\cfrac{5}{2}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{22}{3}-\cfrac{5}{2}\implies \stackrel{\textit{using an LCD of 6}}{\cfrac{(2)22~~-~~(3)5}{6}}\implies \cfrac{44-15}{6}\implies \cfrac{29}{6}\implies 4\frac{5}{6}[/tex]
