I agree with Val that you should bring it up with the teacher. Kids, in general, want to fit in with their peers, and even if they are proud of how they did on something in school, a teacher can't assume that they want it broadcast. It only sets up an unnecessary and unhelpful competition between the kids. High scorers don't necessarily like it and low-scorers hate it. IMO, grades should be private, and it is up to the child who earned the grade to decide if he wants to tell his classmates about it.
Cat, I think you did a nice job of handling the situation with your DS, though! It sounds like you remained calm, hit upon both innate ability and working hard, and reassured him emotionally. Can't get much better than that!
