Решим пример по действиям:
1) 2$$\frac{1}{4}$$ + 3$$\frac{2}{3}$$ = $$\frac{9}{4}$$ + $$\frac{11}{3}$$ = $$\frac{27}{12}$$ + $$\frac{44}{12}$$ = $$\frac{71}{12}$$
2) 8$$\frac{5}{10}$$ – 1$$\frac{2}{5}$$ = 8$$\frac{1}{2}$$ - 1$$\frac{2}{5}$$ = $$\frac{17}{2}$$ - $$\frac{7}{5}$$ = $$\frac{85}{10}$$ - $$\frac{14}{10}$$ = $$\frac{71}{10}$$
3) $$\frac{71}{12}$$ $$\div$$ $$\frac{71}{10}$$ = $$\frac{71}{12}$$ $$\cdot$$ $$\frac{10}{71}$$ = $$\frac{10}{12}$$ = $$\frac{5}{6}$$
4) $$\frac{5}{6}$$ $$\div$$ 1,2 = $$\frac{5}{6}$$ $$\div$$ $$\frac{12}{10}$$ = $$\frac{5}{6}$$ $$\cdot$$ $$\frac{10}{12}$$ = $$\frac{50}{72}$$ = $$\frac{25}{36}$$
Ответ: $$\frac{25}{36}$$