Answer
$-13+7=-6$
$\ \ \ \ \ \ \ \curvearrowright\:\curvearrowright\:\curvearrowright\:\curvearrowright\:\curvearrowright\:\curvearrowright\:\curvearrowright$
$\overline{\ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ }$
$\overset{-1\ \ -1\ \ -1\ \ -1\ \ -1\ \ -9\ \ -8\ \ -7\ \ -6\ \ -5\ \ -4\ \ \ -3\ \ -2\ \ -1\ \ \ \ \ 0\ \ \ \ \ \ 1\ \ \ \ \ 2\ \ \ \ \ 3}{ }$
$\overset{\ \ \ 4\ \ \ \ \ 3\ \ \ \ \ \ 2\ \ \ \ \ 1\ \ \ \ \ 0\ \ }{ }$
Work Step by Step
To add 7, begin at -13 and move 7 spaces to the right.