Alternatively, if number theory pls try MAGMA http://magma.maths.usyd.edu.au/magma/ from http://www.dms.umontreal.ca/wiki/index.php?title=Magma&action=e or 1 down vote >>after SAGE try PARI/GP and then MAGMA share|improve this answer answered Oct 11 '09 at 0:21 Re original query: >Best open-source Mathematica equivalent [closed] >What is the best open-source equivalent for Mathematica? My requirements are: >(most important) Must be a real computer algebra system (CAS). Notably, I don't want Matlab clones -- I want something that can, at least, symbolically differentiate and integrate. Must be programmable. A functional-programming view of the world, like Mathematica's, would be awesome. The basic datatype of M'ica is the list, which is very convenient! (least important) Similar syntax would be nice. The ability to deal with objects such as groups or graphs would be a great bonus, but my primary emphasis is on the main things Mathematica and Maple do: algebra and calculus, both symbolic and numeric. Also, plotting is not high on my list of requirements, as I'm mostly a terminal and not GUI user. http://stackoverflow.com/questions/33550/best-open-source-mathe