SageMath
is built out of 
hundreds of open-source packages and features a unified
interface.
SageMath can be used to study elementary and advanced, pure
and applied mathematics. This includes a huge range of mathematics,
including basic algebra, calculus, elementary to very advanced number
theory, cryptography, numerical computation, commutative algebra,
group theory, combinatorics, graph theory, exact linear algebra and
much more.
It combines 
various software packages 
and seamlessly
integrates their functionality into a common experience.  It is 
well-suited
for education and research.
The user interface is a
notebook in a web browser or the command line. Using the notebook,
SageMath connects either locally to your own SageMath installation or to a
SageMath server on the network. Inside the SageMath notebook you can create
embedded graphics, beautifully typeset mathematical expressions, add
and delete input, and share your work across the network.
 
 
  The following showcase presents some of SageMath's capabilities, screenshots and gives you an
  overall impression of what SageMath is. The examples show the lines of code in SageMath on the left side,
  accompanied by an explanation on the right. They only show the very basic concepts of how SageMath
  works. Please refer to the 
documentation material for more detailed
  explanations or 
visit the library to see SageMath in action.