[tex]7\dfrac{1}{5}=\dfrac{7\cdot5+1}{5}=\dfrac{35+1}{5}=\dfrac{36}{5}\\\\6\dfrac{2}{5}=\dfrac{6\cdot5+2}{5}=\dfrac{30+2}{5}=\dfrac{32}{5}\\\\7\dfrac{1}{5}-6\dfrac{2}{5}=\dfrac{36}{5}-\dfrac{32}{5}=\dfrac{36-32}{5}=\boxed{\dfrac{4}{5}}[/tex]
[tex]7\dfrac{1}{5}-6\dfrac{2}{5}=(7-6)+\left(\dfrac{1}{5}-\dfrac{2}{5}\right)=1+\dfrac{1-2}{5}=1+\dfrac{-1}{5}=1-\dfrac{1}{5}\\\\=\dfrac{5}{5}-\dfrac{1}{5}=\dfrac{5-1}{5}=\boxed{\frac{4}{5}}[/tex]
