I'm fully in the camp of not telling, but sometimes I would really love to. DS9 really doesn't believe he is notably smart. He accepts that he must be quite intelligent, as he's in a GT program, but as his abilities are skewed very clearly toward language rather than Math, he thinks all the Math whizzes out there (including his younger brother) are way smarter than him. Also, in his opinion Mom just thinks he's smart because all Moms think that! I'd love to show him some 'proof' but think it's better in the long run to let him figure it out for himself (you'd think those MAP scores and Grades might give it away!) Another part of me just loves that he doesn't think he's 'all that'.