# Operations on sets II

#### bergausstein

##### Active member
just want to make sure if my answer is correct

If $\displaystyle U\,=\,\{0,\,1,\,2,\,3,\,4,\,5,\,6,\,7,\,8,\,9\}$, the set of digits in our decimal system, and $\displaystyle A\,=\,\{0,\,1,\,2,\,3,\,4,\,5\}$, $\displaystyle B\,=\,\{2,\,3,\,4,\,5,\}$, $\displaystyle C\,=\,\{4,\,5,\,6,\,7\}$, $\displaystyle D\,=\,\{6,\,7,\,8,\,9\}$, find and tabulate:

a. $\displaystyle B'\,\cup\,D'$
b. $\displaystyle A'\,\cup\,B'$

here's my solution

$\displaystyle B'\,\cup\,D'\,=\,\{0,\,1,\,6,\,7,\,8,\,9\}\cup\{0,\,1,\,2,\,3,\,4,\,5,\}\,=\,U$
$\displaystyle A'\,\cap\,B'\,=\,\{6,\,7,\,8,\,9\}\cap\{0,\,1,\,6,\,7,\,8,\,9\}\,=\,\{\,6,\,7,\,8,\,9\}\,=\,D$