You may have used the expression $\displaystyle\frac{{2}}{{3}}\div{18}\usepackage{cmbright}\Huge\$ . This would show how many packages of 18 there are in $\displaystyle\frac{{2}}{{3}}\usepackage{cmbright}\Huge\$ . You need to find how many $\displaystyle\frac{{2}}{{3}}\usepackage{cmbright}\Huge\$ are in 18. $\displaystyle{18}\div\frac{{2}}{{3}}\usepackage{cmbright}\Huge\$