## Thinking Mathematically (6th Edition)

$IV$ region
When we reverse the digits of $17$, we get $71$. This means that $17$ is not a palindromic number. $17$ is not an even number. A - the set of palindromic numbers B - the set of even numbers $17$ belongs in neither A nor B; therefore, it belongs in the region that is outside of the circle for A as well as the circle for B: the $IV$ region.