I see you've uploaded an image containing math problems. I will extract the relevant problem and assist with solving it.

From the image, Problem 23 is:

23. $U = \{x : x \leq 10, x \in \mathbb{N} \}, A = \{x : x \in \mathbb{N}, x \text{ is prime}\}, B = \{y : y = 2x, x \in \mathbb{N}, x \text{ is even}\}$. Write $A \cap B'$ in roster form.

Let's break this down and solve it:

1. $U = \{1, 2, 3, 4, 5, 6, 7, 8, 9, 10\}$, which is the universal set of natural numbers less than or equal to 10.

2. $A$, the set of prime numbers less than or equal to 10, is $A = \{2, 3, 5, 7\}$.

3. $B$, the set of numbers that are twice an even natural number (i.e., $y = 2x$, where $x$ is even), is derived as follows:

   • $x \in \{2, 4, 6, 8, 10\}$, so $B = \{4, 8\}$.

4. Now, $B'$ is the complement of $B$ in $U$, so: $B' = U - B = \{1, 2, 3, 5, 6, 7, 9, 10\}$

5. Finally, $A \cap B'$ is the intersection of $A$ and $B'$: $A \cap B' = \{2, 3, 5, 7\}$

Therefore, $A \cap B'$ in roster form is $\{2, 3, 5, 7\}$.

Let me know if you need further details or explanations!

Relative Questions:

1. What is the complement of a set and how do we calculate it?
2. How are prime numbers defined, and what is their significance in number theory?
3. How does set intersection work, and what are some real-world examples of its use?
4. What are the natural numbers, and how do they differ from other types of numbers?
5. What properties do even numbers have that are useful in problems like this?

Tip:

When working with sets, always define the universal set clearly, as it affects how you compute complements and intersections.