Add the first two numbers. Because they are both positive, you can add as usual ( $\displaystyle{8}+{35}={43}\usepackage{cmbright}\Huge\$ ). Now add $\displaystyle{43}+{\left(-{56}\right)}\usepackage{cmbright}\Huge\$ . Because the two numbers have different signs, you need to find the difference of their absolute values ( $\displaystyle{56}-{43}={13}\usepackage{cmbright}\Huge\$ ). Since $\displaystyle{\left|-{56}\right|}>{\left|{43}\right|}\usepackage{cmbright}\Huge\$ , the result is negative.