Some teachers enjoy GT kids.
Some are exasperated by them, but appreciate their academic curiosity and drive.
(My son had/has some great teachers who fit this category.)
Some tolerate them with no recognition of their aptitude.
Some cut them down verbally.
Some abuse their power by manipulating grades so a kid appears deficient in some area/s
This may include:
Inequitable nit picking
Unexpected heavy weight assigned for whatever the child performed poorly on
Ignoring established parameters (such as end of grading period)
Changing the �rules� mid-stream
With-holding pertinent information
Lying about �missing� work to lower over-all average
Unknown or convoluted grading matrixes
If there has been a CHANGE (since your conversation) in the way this teacher grades all the math tests, or if he only deducts points for missing $ signs on your son�s tests, then you are probably dealing with the last example. A pattern in behavior is the best indicator.
BTW, my work involves defining and identifying work-place disparate treatment (which really isn�t as subjective as most people imagine) and recommending best practices to reduce actual or perceived discrimination. Kids can be especially vunerable to "bad apple" teachers.
Unfortunately, parents often do not address the innappropriate actions for fear of reprisal which is a very real possibility with a true "bully" teacher.
If you are afraid (for your son) to confront the teacher or principle, just record the occurence in case the situation continues of escalates. There is a possibily that the teacher will realize his angry reaction and stop it. I wouldn't hold my breath for an appology though.