I guess it makes sense that they don't 'see' when a child is mathematically gifted as easily.
My DS6 was doing 2nd-3rd grade math last year in K and my DD5 is capable of doing 1st grade math with no issues in K. I know many kids who are ahead of the K math here but not necessarily gifted in math just had parents who helped them learn. It seems easy to be ahead of K math at least from my exposure to it anyways.
DS6 dislikes long division -- but he enjoys the short division way they taught him in k12 3rd grade math

I have to make him do the long way occasionally so he doesn't forget it.