## Thinking Mathematically (6th Edition)

$II$ region
When we reverse the digits of $22$ we get $22$. This means that $22$ is a palindromic number. $22$ is an even number. A - the set of palindromic numbers B - the set of even numbers $22$ belongs in A as well as B; therefore, it belongs in the region that is inside of the circle for A as well as the circle for B: the $II$ region.