You may have incorrectly crossed out the 2s getting $\displaystyle\frac{{1}}{{3}}\usepackage{cmbright}\Huge\$ . This is not the same as dividing by a common factor. Although $\displaystyle\frac{{1}}{{3}}\usepackage{cmbright}\Huge\$ is in lowest terms, it is not equivalent to $\displaystyle\frac{{12}}{{32}}\usepackage{cmbright}\Huge\$ .