A standard six-sided number cube (die) has three even numbers: 2, 4, and 6. Therefore, the probability of rolling an even number is:
\[ P(\text{even number}) = \frac{\text{number of even outcomes}}{\text{total outcomes}} = \frac{3}{6} = \frac{1}{2} \]
If the die is rolled 30 times, the expected number of times it will land on an even number is calculated by multiplying the probability of rolling an even number by the number of rolls:
\[ \text{Expected rolls of even number} = P(\text{even number}) \times \text{number of rolls} = \frac{1}{2} \times 30 = 15 \]
Therefore, you can expect to roll an even number approximately 15 times.