writing/small motor issues and writing math

I have a student whose writing is very poor and takes a long time. He likes to do his math in his head. Now that he is in 8th grade and doing Algebra this is getting harder for him. As I can't see inside his head, I can't show him where his mistakes are. Is there some kind of program where a student can use the computer to type out algebra problems? It can have a calculator in it, but I don't want it to do the problem for him.