I just learned about this software from my mathematician son, and I think 
it looks like a pretty nice, well-developed system for symbolic math:

http://en.wikipedia.org/wiki/Sage_(mathematics_software)

It's using Python and is GPL.

But when I try to install it, I run into trouble.  Any ideas about this?:

I'm using the code here for Ubuntu PPA:

http://www.sagemath.org/download-linux.html

Install Sage this way:

apt-add-repository -y ppa:aims/sagemath
apt-get update
apt-get install sagemath-upstream-binary

I ran those three lines, always preceded with "sudo", but the output from 
that last line was this:

E: Package 'sagemath-upstream-binary' has no installation candidate

Any ideas?  Maybe I need to contact the Sage team about that.

Mike