Reverse Psychology

I have a fifth grader who I will call "Tommy." Tommy has had a hard homelife and struggles with self-esteem problems which are just magnified by his lack of abilities and desire. He's been tested for learning problems, but he CAN do it...he just decides he's "stupid" and doesn't try whenever he hits a wall. So...begins the story...
After one math lesson (like many) he is saying under his breath during the whole thing..."math is stupid...I hate math...this is dumb" After the lesson I ask him if he needs some help and of course he's in is defeatist attitude and everything is "stupid." So, all of a sudden he hears Mr.Gehrke say, "YEAH! THIS MATH IS STUPID! SOOOOO STUPID! IT'S EVEN DUMB! LET'S SHOW THIS MATH HOW DUMB IT IS BY BEATING IT AND FINISHING IT!!!...WHAT DUMB MATH!!" He had no idea what to do, nothing to say and I wanted to laugh so hard at myself, but I think all of a sudden he heard what he sounded like and it sparked something inside. I just couldn't believe it worked...I just thought...might as well...nothing else has worked. I'm pleased to say after a few other things he has had a good couple weeks. Tommy is hopefully on his way...finally.