# Abscissa > Abscissa and Mathsys documentation. ## Docs - [Addition and subtraction](https://docs.abscissa.eu/Mathsys/Learn/Addition-and-subtraction.md): Learn how to add and subtract. - [Comments](https://docs.abscissa.eu/Mathsys/Learn/Comments.md): Learn how comment in your code. - [Declarations and definitions](https://docs.abscissa.eu/Mathsys/Learn/Declarations-and-definitions.md): Learn how declare and define variables. - [Exponentiation](https://docs.abscissa.eu/Mathsys/Learn/Exponentiation.md): Learn how to use exponents. - [Getting Started](https://docs.abscissa.eu/Mathsys/Learn/Getting-started.md): Get started with Mathsys - a mathematical programming language designed for natural mathematical expression. - [Infinite](https://docs.abscissa.eu/Mathsys/Learn/Infinite.md): Learn the infinite keyword. - [Limits](https://docs.abscissa.eu/Mathsys/Learn/Limits.md): Learn how to type limits. - [Modules](https://docs.abscissa.eu/Mathsys/Learn/Modules.md): Learn how to use modules. - [Multiplication and division](https://docs.abscissa.eu/Mathsys/Learn/Multiplication-and-division.md): How to multiply and divide in Mathsys - [Tensors](https://docs.abscissa.eu/Mathsys/Learn/Tensors.md): Learn about vectors and tensors. - [Type declarations](https://docs.abscissa.eu/Mathsys/Learn/Type-declarations.md): Learn how to specify the types of values. - [Variables](https://docs.abscissa.eu/Mathsys/Learn/Variables.md): Learn variables and their features. ## Optional - [Abscissa](https://github.com/alejandro-vaz/abscissa) - [Mathsys](https://github.com/alejandro-vaz/mathsys)