$$\left. \begin{array} { l } { \frac { 4 } { 7 } + ( \frac { - 4 } { 9 } ) + \frac { 3 } { 7 } + ( \frac { - 13 } { 9 } ) } \end{array} \right.$$
$-\frac{8}{9} = -0.8888888888888888$
