If $A = \{1, 2, 3, 4, \dots, 10\}$, then the number of non-empty subsets of $A$ containing only even numbers is

Consider the sets $\phi, A = \{1, 3\}, B = \{1, 5, 9\}, C = \{1, 3, 5, 7, 9\}$. Insert the symbol $\subset$ or $\not\subset$ between the following pair of sets: $\phi \dots B$.

Which of the following is an example of the null set?
$\{ x : x \in \mathbb{N}, x < 5 \text{ and } x > 7 \}$

If $A, B$,and $C$ are three sets,then $A \times (B \cup C)$ is equal to

Which of the following is a subset of every set?

List all the elements of the following set:
$B = \{ x : x \text{ is an integer}; -\frac{1}{2} < x < \frac{9}{2} \}$