We have a meeting tomorrow about this and about a number of other problems I have with this teacher. It is only with the resource teacher, principal, bad math teacher and DH and I. So I am also wondering do I need to make it an IEP meeting?
ITA with BSM re being able to call an IEP meeting at any time, but I wouldn't attempt to change the meeting tomorrow into an IEP meeting. Try to see if you can make headway with the issues in math class at this meeting, be sure to come out of the meeting with a plan (if one can be agreed upon), and then if that plan doesn't work and your ds continues to have stress and anxiety over how he's being treated in his math class, that's the time to call an IEP update meeting.
Re whether or not you can ask for an accommodation as you mentioned above, I'd pass that question on to your local advocate (I think you have an advocate?). You can absolutely have accommodations to address anxiety, but I think I'd want an advocate to advise me re how to phrase the specifics of the accommodation.
Good luck - let us know how the meeting goes.
polarbear
