28,8:13 5/7+6,6:2/3 все делим 1 11/16:2,25

[latex] \frac{28,8: 13 \frac{5}{7}+6,6: \frac{2}{3} }{1 \frac{11}{16}:2 \frac{1}{4} } = \frac{ \frac{144}{5}* \frac{7}{96} + \frac{33}{5} *\frac{3}{2} }{\frac{27}{16}* \frac{4}{9} }= \frac{ \frac{21}{10} + \frac{99}{10} }{ \frac{3}{4} } = \frac{12}{ \frac{3}{4} } =16[/latex]