To find the probability of picking number 2 or 3 from the sample space \( S = {1, 2, 3} \), we first determine the total number of outcomes in the sample space, which is 3.
The favorable outcomes for picking either number 2 or number 3 are:
- Number 2
- Number 3
Thus, there are 2 favorable outcomes (2 and 3).
Next, we calculate the probability using the formula:
\[ P(\text{picking 2 or 3}) = \frac{\text{number of favorable outcomes}}{\text{total number of outcomes}} = \frac{2}{3} \]
Therefore, the probability of picking number 2 or 3 is
\[ \frac{2}{3} \]