Question 4
Find $\mathbf{A} \cap \mathbf{B}$ given the following sets:
\[
\begin{array}{l}
\mathbf{U}=\{x \mid x \in \mathbf{N} \text { and } x \leq 10\} \\
\mathbf{A}=\{10,7,6,8,9,2\} \\
\mathbf{B}=\{1,8,5,7,6\}
\end{array}
\]
Give your answer as an ordered set. For example, $\{a, b, c, d\}$.

Step 1 ：Given sets A and B as follows:

Step 2 ：\[\mathbf{A} = \{10,7,6,8,9,2\}\]

Step 3 ：\[\mathbf{B} = \{1,8,5,7,6\}\]

Step 4 ：We are asked to find the intersection of sets A and B. The intersection of two sets is the set of elements that are common to both sets.

Step 5 ：Comparing the elements of sets A and B, we find that the common elements are 6, 7, and 8.

Step 6 ：So, the intersection of sets A and B is \[\mathbf{A} \cap \mathbf{B} = \{6, 7, 8\}\]

Step 7 ：Finally, we are asked to present the answer as an ordered set. An ordered set is a set in which the order of elements matters. In this case, we can order the elements in ascending order.

Step 8 ：Thus, the ordered intersection of sets A and B is \[\mathbf{A} \cap \mathbf{B} = \{6, 7, 8\}\]

Step 9 ：Final Answer: The intersection of sets A and B is \(\boxed{\{6, 7, 8\}}\)