I've been thinking about math mistakes a lot today. None of us really like to make mistakes, but it seems like math mistakes can cause a remarkably high amount of stress in certain kids.
My daughter went through a phase in Kindergarten when she HATED making mistakes.
Here are 5 things that helped her, in no particular order:
1) We talk about the "growth mindset." A LOT. We talk about how her mind gets stronger when she struggles and then learns something new.
2) We laugh together at the idea of there being "a math person," to try to take away her fear that she isn't one! The idea that you are either born good at math or not is scary to kids. It distorts mistakes from what they really are: normal healthy struggle to learn!
3) I sometimes let her see me struggle with something. Anything! And I show her that I am confident that if I don't give up, I'll figure something out.
4) I include some bonus fun in the MathKit games for when she makes a mistake, like flying her in the air after she fixes it.
5) I remind her that if she is always getting the right answer without any mistakes, she's learning stuff that is too easy! As a teacher, I want students to be in the sweet spot, where it isn't too easy or too hard.
This is a complicated problem, but I hope some of these ideas will work for you!