A standard number cube, commonly known as a die, has 6 faces, each showing a different number from 1 to 6.
To find the probability of not rolling a 4, we first determine the total number of possible outcomes when rolling the die, which is 6. The event of "not rolling a 4" includes rolling any of the other numbers: 1, 2, 3, 5, or 6.
There are 5 outcomes that result in not rolling a 4 (1, 2, 3, 5, and 6).
Now, we can calculate the probability:
\[ P(\text{not 4}) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{5}{6} \]
Therefore, the probability of not rolling a 4 is \(\frac{5}{6}\).