While calculating $\displaystyle{4}{{\left(-{4}\right)}}^{{2}}-{3}{\left(-{4}\right)}\usepackage{cmbright}\Huge\$ , you may have thought that $\displaystyle{{\left(-{4}\right)}}^{{2}}\usepackage{cmbright}\Huge\$ is negative, and also gotten the wrong sign for $\displaystyle{\left(-{3}\right)}{\left(-{4}\right)}\usepackage{cmbright}\Huge\$ . Whenever you square a negative number, you get a positive result. Whenever you multiply two negative numbers, you get a positive result.