I think all kindergarten teachers like to know that the kids are happy. If the math being easy is making your kid unhappy, I think that is worth bringing up to the teacher. But like others have said, what is your goal? Is the grade level instruction too easy, or just the homework? Do you want to substitute harder homework? Do you want to see if he can go up a grade for math? First figure out what you want, and then go talk with the teacher. I don't think asking for something like the ability to learn new material, just like all the other kids get to do, should make you "That Mom". And who cares if it does? You can be That Mom if it works.
