let's firstly convert the mixed fractions to improper fractions.
[tex]\bf \stackrel{mixed}{1\frac{1}{3}}\implies \cfrac{1\cdot 3+1}{3}\implies \stackrel{improper}{\cfrac{4}{3}}~\hfill \stackrel{mixed}{2\frac{2}{5}}\implies \cfrac{2\cdot 5+2}{5}\implies \stackrel{improper}{\cfrac{12}{5}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{4}{3}+\cfrac{12}{5}\implies \stackrel{\textit{using an LCD of 15}}{\cfrac{(5)4+(3)12}{15}}\implies \cfrac{20+36}{15}\implies \cfrac{56}{15}\implies 3\frac{11}{15}[/tex]