OK, not really assistive technology, but may be helpful...
Some of our high school students have a hard time practicing higher math (algebra I, geometry, etc.) because so much of it hinges upon the pencil-and-paper practice examples. Try these websites to shore up their understanding without any need for handwriting!
http://nlvm.usu.edu/en/NAV/grade_g_4.html
http://www.brainpop.com/math/
http://www.regentsprep.org/Regents/math/ALGEBRA/games/Aquiapage.htm
http://math.cudenver.edu/~rbyrne/flash.htm
http://www.shodor.org/interactivate/activities/
http://www.intmath.com
http://www.mathwords.com/ and http://www.mathwords.com/index_applications.htm
http://education.jlab.org/solquiz/index.html