Continuity mistake: When Jack is in his new classroom for the first time, he sits at a metal desk. He falls with the desk when he tries to reach his book bag, which is sitting next to a broken wooden desk. Next, he sits in the same - miraculously whole - wooden desk, then proceeds to break it to smithereens.
Suggested correction: Watched several times, he moves to the desk to the left of him that doesn't have a chair attached.