My feeling is that if they clearly know the material, then they should have appropriate material in place of the classroom work. It doesn't make sense to do both. My DS5 is in first and I do believe that sometimes he has to do the same work they do, and other times he doesn't. I have recently started more discussions on this as I don't think that makes sense. I think they are just figuring all this out. They are going to start giving him his own spelling words, which is a good start. He was getting frustrating having to write his 2 and 3 letter words 3x each. His math homework that comes home is the most basic thing ever and his teacher told me that I was welcome to make it more appropriate to him and challenging to him...which is a good start but I have no idea how to turn an assignment that says something like "what number comes after 10?" into something challenging for him. So they are looking into some more appropriate stuff hopefully. I think he gets to read books in the classroom while they are learning to read. But he still does the handwriting and journal stuff that the other kids do, which makes sense.
In bringing it up with the school I would just mention that you are really excited that they have been able to challenge him some with Math and reading, but that you were wondering if his math is in place of the other math or if it is in addition to the other math. I would say that he really enjoys the challenging math but that you had noticed him become frustrated when given the other sheets. Something like that would clearly acknowledge you are grateful for what they are doing. I am not expert but those are my thoughts. : )
