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

Show that if $A \subset B$,then $(C - B) \subset (C - A)$.

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

State which of the following sets are finite or infinite:
$A = \{ x : x \in \mathbb{N} \text{ and } x \text{ is prime} \}$

From the sets given below,select equal sets:
$A=\{2,4,8,12\}, B=\{1,2,3,4\}, C=\{4,8,12,14\}, D=\{3,1,4,2\}$
$E=\{-1,1\}, F=\{0, a\}, G=\{1,-1\}, H=\{0,1\}$

Make correct statements by filling in the symbols $\subset$ or $\not\subset$ in the blank spaces:
${ x:x \text{ is a circle in the plane} } \dots { x:x \text{ is a circle in the same plane with radius } 1 \text{ unit} }$