I enjoyed this article (link is to pdf file) quite a bit, and I think it's worth sending it to math teachers if you can do it in a way that they will look at it.

I had not previously put in the same place my thoughts on growth mindset vs. fixed mindset and my thoughts on fast vs. deep thinking in math. As a parent of a child who is extremely capable in math but not fast at all (and tends to make careless mistakes), it gave me some food for thought in how to talk to her about math.