You can get 13 by using the number 4 four times like this:

$13 = 4 \times 4 - \frac{4}{4}$

Here's how it works:

1. $4 \times 4 = 16$
2. $\frac{4}{4} = 1$
3. $16 - 1 = 13$

This gives the result 13, using the number 4 exactly four times.

Would you like further details on number manipulation techniques, or have any other questions?

Here are some related questions to consider:

1. Can you use four 5s to get 25?
2. What are other ways to achieve 13 using only four 4s?
3. Can you use four 4s to get a result of 20?
4. How can we make other numbers using only four 4s?
5. What if we only used three 4s – what’s the highest number we could achieve?

Tip: When solving problems that limit you to certain numbers or operations, think creatively with basic math operations: addition, subtraction, multiplication, division, and parentheses can often unlock surprising solutions!