First substitute 9 for l and 7 for w in the expression $\displaystyle{l}\cdot{w}\usepackage{cmbright}\Huge\$ and then multiply: $\displaystyle{9}\cdot{7}={63}\usepackage{cmbright}\Huge\$ . Next substitute 8 for l and 8 for w in the expression and then multiply: $\displaystyle{8}\cdot{8}={64}\usepackage{cmbright}\Huge\$ . The larger floor area is 64.