You probably found the correct product $\displaystyle{50.38}\times{{10}}^{{7}}\usepackage{cmbright}\Huge\$ , but when converting 50.38 to scientific notation, you incorrectly wrote it as $\displaystyle{5.038}\times{{10}}^{{-{{1}}}}\usepackage{cmbright}\Huge\$ , instead of $\displaystyle{5.038}\times{{10}}^{{1}}\usepackage{cmbright}\Huge\$ .