3. From six cards numbered $1, 2, \cdots, 6$, any three cards are drawn. Then the probability that the numbers on the drawn cards are all greater than or equal to 2 is $\qquad$.
3. $\frac{1}{2}$.

There are 20 possible ways to draw three cards from six cards. There are 10 possible ways where the card numbers are all greater than or equal to 2, so the required probability is $p=\frac{10}{20}=\frac{1}{2}$.