I agree with aculady. If your child has a fluency, storage/ retrieval, memory or processing disability that impairs his ability to access the curriculum and make appropriate progress without the use of accommodations including a calculator, then he should get them. Additionally, if he needs any modifications such as specialized instruction, this should be part of his IEP.
Is he currently on an IEP? Does it document the use of a calculator? If so, the accommodations are not up for debate.
Be sure that he is aware of the accommodations and help coach him about how to self advocate. It is hard for a MS student - but an important skill. Hopefully this teacher will comply - if not, I would try to move him to a more enlightened teacher.
Good luck.
