Answer
$9+(-4)=5$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \curvearrowleft\:\curvearrowleft\:\curvearrowleft\:\curvearrowleft\:$
$\overline{\ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ |\ \ \ \ }$
$\overset{-9\ \ -8\ \ -7\ \ -6\ \ -5\ \ -4\ \ -3\ \ -2\ \ -1\ \ \ \ \ 0\ \ \ \ \ \ 1\ \ \ \ \ 2\ \ \ \ \ 3\ \ \ \ \ \ 4\ \ \ \ \ 5\ \ \ \ \ 6\ \ \ \ \ \ 7\ \ \ \ \ 8\ \ \ \ \ 9}{ }$
Work Step by Step
To add -4, move 4 units to the left on the number line.