[tex]\it \dfrac{^{7)}9}{\ 10}-\dfrac{^{5)}13}{\ 14}-\dfrac{1}{9}:\dfrac{28}{27}=\dfrac{63-65}{70}-\dfrac{1}{\not9}\cdot\dfrac{\not27\ ^3}{28}=\dfrac{\ \ -2^{(2}}{70}-\dfrac{3}{28}=\\ \\ \\ =-\dfrac{^{4)}1}{\ \ 35}-\dfrac{^{5)}3}{\ \ 28}=\dfrac{-4-15}{140}=-\dfrac{19}{140}[/tex]
