This is the correct sum, but it is not a simplified mixed number, which is a whole number and a proper fraction.

$\displaystyle{5}+\frac{{13}}{{12}}={5}+{1}\frac{{1}}{{12}}={6}\frac{{1}}{{12}}\usepackage{cmbright}\Huge\$ . The correct answer is $\displaystyle{6}\frac{{1}}{{12}}\usepackage{cmbright}\Huge\$ .