Divide the volumes, regroup, and divide the numbers:

$\displaystyle\frac{{{1.41}\times{{10}}^{{18}}}}{{{1.09}\times{{10}}^{{12}}}}={\left(\frac{{1.41}}{{1.09}}\right)}{\left(\frac{{{{10}}^{{18}}}}{{{{10}}^{{12}}}}\right)}={\left({1.29}\right)}{\left(\frac{{{{10}}^{{18}}}}{{{{10}}^{{12}}}}\right)}\usepackage{cmbright}\Huge\$

Use the quotient rule: $\displaystyle{1.29}\times{{10}}^{{{18}-{12}}}={1.29}\times{{10}}^{{6}}\usepackage{cmbright}\Huge\$