$A=\left\{1,2,3,6,9,18\right\}$

$B=\left\{1,2,7,14\right\}$

$A\cup B=\left\{1,2,3,6,7,9,14,18\right\}$

$A\cap B=\left\{1,2\right\}$

$A\backslash B=\left\{3,6,9,18\right\}$

$B\backslash A=\left\{7,14\right\}$