$A={{\left( 2-1\frac{2}{5} \right)}^{2}}+\left| 1-\frac{12}{5} \right|-{{\left( \frac{-2}{5} \right)}^{2}}$

$=\frac{9}{25}+\frac{7}{5}-\frac{4}{25}=\frac{8}{5}$

$B=\frac{1}{2}-\frac{3}{7}:\left( -2\frac{1}{7} \right)+\left| \frac{1}{5}-\frac{1}{2} \right|-\frac{2}{5}$

 $\,=\frac{1}{2}+\frac{1}{5}+\frac{3}{10}-\frac{2}{5}$

$\,=\frac{3}{5}$

VẬY tỉ số:

$\frac{A}{B}=\frac{8}{5}:\frac{3}{5}=\frac{8}{3}$