Answer
$-3 \lt -\dfrac{5}{2}$
Work Step by Step
Note that:
$-3 = -\dfrac{6}{2}$
On a number line, $-\dfrac{6}{2}$ is to the left of $-\dfrac{5}{2}$.
Thus,
$-\dfrac{6}{2} \lt -\dfrac{5}{2}$
Therefore,
$-3 \lt -\dfrac{5}{2}$