Subset Math Example 1

Solution

1. 1
   Recall the definition: $B \subseteq A$ means every element of $B$ is also an element of $A$. We check each element of $B$ individually.
2. 2
   Check $2 \in B$: is $2 \in A = \{1,2,3,4,5\}$? Yes. Check $4 \in B$: is $4 \in A$? Yes.
3. 3
   Since every element of $B$ belongs to $A$, we conclude $B \subseteq A$. Note also $B \ne A$ since $A$ has elements (1, 3, 5) not in $B$, so $B$ is a proper subset: $B \subsetneq A$.