I would avoid saying anything that the teacher might construe as criticism...I try to focus on the district or school curriculum rather than the teacher. So, for instance, I say things like "The curriculum is inappropriate since she already knows the material" rather than saying "My daughter is bored in your class." Also, phrase things as suggestions rather than things they need to do. (Teachers don't want to be micromanaged). So you could suggest sending in a workbook with more appropriate math. Or send in a chapter book that she's in the middle of at home. Act like you symptathize and understand how difficult it must be but want to offer help.
Check to see what your district's policy is on gifted kids (if they have any at all). Do they subject accelerate? Grade accelerate? Level kids according to ability? Have special pull-out programs? Here they have gifted cluster and a special gifted school-within-a-school (for highly gifted) but for K-2 the only options are grade or subject acceleration. The teacher didn't seem to know how to handle it in the classroom (having a kid so far ahead of the others) so we ended up going through the official district protocol of grade acceleration. They gave DD a cognitive abilities test and achievement tests in math and reading. And did some observations to make sure she was mature enough (turned out she has ADHD which I wish they would have picked up on--it's hard to see in kids that young).
But she is doing great--now 7 and in third grade and still at the top of the class for reading and math. Might be something to consider if the school will allow it, and will not give her work at her level within her normal grade. It's frustrating. I'm dealing with it with my DS as well. He has a disability so I don't want to grade accelerate him, but the teacher seems to be at a loss as to how to handle him. He is in first grade and at a third-fourth grade level for reading and math. It's not hard to have him read harder level books, but not so easy for math.
