Answer
$\frac{2}{3}$
Work Step by Step
We know that $probability=\frac{\text{number of favourable outcomes}}{\text{number of all outcomes}}$
The total number of possibilities (the number of all outcomes) obviously is $6$
Out of the $6$, there are $4$, that are lower than $3$ or bigger than $4$, thus there are $4$ "good outcomes".
Hence the probability here is: $\frac{4}{6}=\frac{2}{3}$
