Problem
Let $A=\{2,5,6,13,15\}$ and $E=\{6\}$. Insert $\subseteq$ or $\nsubseteq$ to make the statement true. Insert $\subseteq$ or $\nsubseteq$ to make the statement true. $\mathrm{A} \nabla \mathrm{E}$
Solution
Step 1 ：Let $A=\{2,5,6,13,15\}$ and $E=\{6\}$. We are asked to insert $\subseteq$ or $\nsubseteq$ to make the statement true.
Step 2 ：The question is asking whether set A is a subset of set E or not. A subset is a set whose elements are all members of another set.
Step 3 ：In this case, set A is $\{2,5,6,13,15\}$ and set E is $\{6\}$. We can see that not all elements of set A are in set E.
Step 4 ：Therefore, A is not a subset of E. We should use the symbol $\nsubseteq$ to make the statement true.
Step 5 ：\(\boxed{A \nsubseteq E}\) is the final answer.
