Question:
State in each case whether A ⊂ B or A ⊄ B.
$A=\{x: x$ is an integer $\}, B=\{x: x$ is a rational number $\}$
Solution:
$A=\{\ldots .-2,-1,0,1,2,3 \ldots\}$
$B=\{-\infty, \ldots \ldots \ldots 0, \ldots \ldots \infty\}$
A ⊂ B as integers are contained in rational numbers.