[tex]\displaystyle\bf\\1)\\\\26\frac{2}{3} :6,4=\frac{80}{3} :\frac{64}{10} =\frac{80}{3} \cdot\frac{5}{32} =\frac{5\cdot 5}{3\cdot 2}=\frac{25}{6} =4\frac{1}{6}\\\\2)\\\\19,2:3\frac{5}{9} =\frac{192}{10} :\frac{32}{9} =\frac{96}{5} \cdot\frac{9}{32} =\frac{3\cdot 9}{5} =\frac{27}{5} =5\frac{2}{5} \\\\3)\\\\4\frac{1}{6} \cdot 5\frac{2}{5} =\frac{25}{6} \cdot \frac{27}{5} =\frac{5\cdot 9}{2} =\frac{45}{2} =22,5[/tex]

[tex]\displaystyle\bf\\4)\\\\8\frac{4}{7} :2\frac{26}{77} =\frac{60}{7} :\frac{180}{77} =\frac{60}{7}\cdot\frac{77}{180} =\frac{11}{3} =3\frac{2}{3} \\\\5)\\\\0,5:18\frac{2}{3} \cdot11=\frac{1}{2}\cdot\frac{3}{56} \cdot11=\frac{33}{112} \\\\6)\\\\3\frac{2}{3} :\frac{33}{112} =\frac{11}{3} \cdot\frac{112}{33} =\frac{112}{9} =12\frac{4}{9} \\\\7)\\\\22,5-12\frac{4}{9} -\frac{1}{18} =22\frac{9}{18} -12\frac{8}{18} -\frac{1}{18} =22-12=10[/tex]