Use packages in LaTeX to add more functions. Demonstration of amsmath package and basic math typesetting. LaTeX has a lot of functions by default, but in some situations it can be easier to use packages. To import a package in LaTeX, you simply add the \usepackage directive to the preamble of your document.

When using Linux or Mac, most packages will already be installed by default and it is usually not necessary to install them. In case of Ubuntu installing texlive-full from the package manager would provide all packages available. The MiKTeX bundle in Windows, will download the package if you include it to your document.

There are many packages, all for different purposes in this guide you will find some of the most useful and common used. For writing math, LaTeX offers an environment called equation. Everything inside this environment will be printed in math mode, a special typesetting environment for math. LaTeX also takes care of equation numbers for us:

The automatic numbering is a useful feature, but sometimes it's necessary to remove them for auxiliary calculations. LaTeX doesn't allow this by default,so now we include a package that does: