SageMath is free open-source math software that supports research and teaching in algebra, geometry, number theory, cryptography, numerical computation, and related areas.
System Requirements: Windows, 64-bit Mac OS X 10.8 systems only, or Linux.
Download SageMath from Tigerware
--- SageMath: Installation Instructions (Mac)
SageMath: Installation Guide
SageMath: Reference Manual
SageMath: FAQ
Referenced from sagemath.org