A standard number cube (or die) has six faces, numbered 1 through 6. To find the probability of rolling a prime number, we first identify the prime numbers in this set.

The prime numbers between 1 and 6 are:

• 2
• 3
• 5

This gives us 3 prime numbers out of the 6 possible outcomes on the cube.

Probability Calculation

$\text{Probability of rolling a prime number} = \frac{\text{Number of prime outcomes}}{\text{Total number of outcomes}} = \frac{3}{6} = \frac{1}{2}$

So, the probability of rolling a prime number is $\frac{1}{2}$ or 50%.

Would you like more details or have any questions?

Here are five related questions to explore:

1. What is the probability of rolling an odd number on a number cube?
2. If two number cubes are rolled, what is the probability of getting two prime numbers?
3. What is the probability of rolling a composite number on a number cube?
4. How would the probability change if the cube had numbers from 1 to 8?
5. Can we determine the probability of rolling a number greater than 4?

Tip: Remember, prime numbers are numbers greater than 1 that have only two divisors: 1 and themselves.