To calculate $4!$, we follow the same method of multiplying the numbers from 4 down to 1.

$4! = 4 \times 3 \times 2 \times 1$

Now, calculate step by step:

$4 \times 3 = 12$ $12 \times 2 = 24$ $24 \times 1 = 24$

So, $4! = 24$.

Would you like further details on how factorials work, or do you have other questions?

Here are 5 related questions to explore:

1. How is the factorial of a number used in combinatorics?
2. What is the difference between $5!$ and $6!$?
3. How do factorials relate to permutations and combinations?
4. What is the factorial of 0, and why is it defined that way?
5. Can you simplify $\frac{6!}{4!}$?

Tip: Factorials grow very quickly. For large numbers, it's helpful to use a calculator or software to avoid manual calculation errors.