In the following,state whether $A=B$ or not:
$A=\{4, 8, 12, 16\}; B=\{8, 4, 16, 18\}$

Show that $A \cup B = A \cap B$ implies $A = B$.

Find the union of each of the following pairs of sets:
$A = \{ x : x \text{ is a natural number and a multiple of } 3 \}$
$B = \{ x : x \text{ is a natural number less than } 6 \}$

In the following,state whether $A = B$ or not:
$A = \{ x: x \text{ is a multiple of } 10 \}$
$B = \{ 10, 15, 20, 25, 30, \ldots \}$

Which set is the subset of all given sets?

In this question,all integers are represented in base $10$. Consider the set $E$ of positive integers $n$ having the property that when any nonzero digit $d \in \{1, 2, \dots, 9\}$ is written to the right of $n$,the resulting number is divisible by $d$. Let $N$ be the smallest element of $E$. The product of the digits of $N$ is: