I just got back from 3.5 days at a camp with 15 adolescents with significant disabilities. Most use AAC devices and some sort of alternate computer input. One teenage girl explained to me that she is pretty good in math but she has two problems as she tries to tackle high school math.
1. She needs on onscreen calculator that is scanning accessible and allows her to send the answer from the window on the calculator to the document she has open on her computer. For the most part, her documents are actually scanned omni-page or pdf files - she steps through answer fields using a tab key. Right now, the only option is to copy, minimize, activate the form, and paste - that is really hard for her.
2. She needs some sort of math program that allows her to show her work. There is a program called Math Pad that kind of lets you do this, but it stops at simple multiplications and division.
Also, I've had teachers of the visually impaired ask me for calculators that would enable kids to show their work.