Answer
$\lt$
Work Step by Step
Think of points on the number line, with the given coordinates.
If point A lies to the left of point B on the number line,
then $A\lt B$.
$-3$ lies to the left of $-\displaystyle \frac{5}{2}$, so we write $-3 \displaystyle \lt -\frac{5}{2}$.
