Ответ:

[tex]1) 5\frac{2}{3} +2\frac{1}{6} =5\frac{4}{6}+2\frac{1}{6} =7\frac{5}{6}[/tex]

[tex]2)8\frac{5}{9} +6\frac{7}{12} =8\frac{20}{36}+6\frac{21}{36} =14\frac{41}{36} =15\frac{5}{36}[/tex]

[tex]3)7\frac{2}{5} +1\frac{1}{3} =7\frac{6}{15} +1\frac{5}{15} =8\frac{11}{15}[/tex]