Find sets $A, B$ and $C$ such that $A \cap B, B \cap C$ and $A \cap C$ are non-empty sets and $A \cap B \cap C=\varnothing$

If $A$ and $B$ are any two sets, then $A \cup (A \cap B) $ is equal to

Let $A=\{1,2,3,4,5,6\}, B=\{2,4,6,8\} .$ Find $A-B$ and $B-A$

Find the union of each of the following pairs of sets :

$A = \{ x:x$ is a natural number and multiple of $3\} $

$B = \{ x:x$ is a natural number less than $6\} $

If $A = \{ x:x$ is a natural number $\} ,B = \{ x:x$ is an even natural number $\} $ $C = \{ x:x$ is an odd natural number $\} $ and $D = \{ x:x$ is a prime number $\} ,$ find

$A \cap B$