Answer :
[tex]\dfrac{1}{5}+20.4-\left(-5 \dfrac{3}{5}\right)=\\
\dfrac{1}{5}+20\dfrac{4}{10}-\left(-\dfrac{28}{5}\right)=\\
\dfrac{1}{5}+20\dfrac{2}{5}+\dfrac{28}{5}=\\
\dfrac{29}{5}+\dfrac{102}{5}=\\
\dfrac{131}{5}=26\dfrac{1}{5}
[/tex]