...

print '$z is: ', $z, "\n";
print 'eval of $z is: ', eval $z, "\n";
print 'eval of "2 * 3" is: ', eval '2 * 3', "\n";

##</code><code>##

$z is: 2 * 3
eval of $z is: 6
eval of "2 * 3" is: 6