Correct. Monomials are divided by dividing the coefficients and dividing the variables. When you have the same variable, you can subtract the exponents.

$\displaystyle\frac{{{8}{{a}}^{{6}}{{b}}^{{2}}}}{{{56}{{a}}^{{4}}{{b}}^{{2}}}}=\frac{{8}}{{56}}\cdot\frac{{{{a}}^{{6}}}}{{{{a}}^{{4}}}}\cdot\frac{{{{b}}^{{2}}}}{{{{b}}^{{2}}}}=\frac{{1}}{{7}}\cdot\frac{{{{a}}^{{2}}}}{{1}}\cdot{1}=\frac{{{{a}}^{{2}}}}{{7}}\usepackage{cmbright}\Huge\$

The exponent for the variable a is 2.