Sigh. We had the same problem. Our child's K teacher was convinced he didn't understand basic addition and subtraction because he didn't explain things like 2+1 in the way she wanted. She wouldn't tell us what that way was either, and she wouldn't believe that he could just know the same way that you or I just know that it is. This was also a teacher of gifted children.
My experience was that many teachers of the gifted are really teachers of the moderately gifted but have little understanding of how profoundly different a child who is EG/PG can be from their "typical" MG student.
Sorry, no advice, other than to say I agree with Grinity that the real issue is why she has to do work that they know is below her level.
