Click the extension's icon, and it will open a page. The page has many links that you can click to get to different pages.
These pages explain different parts of math. The subjects are: The basics, basic geometry, Pre-Algebra, Algebra I, Algebra II, Geometry, Trigonometry, and Calculus. So far, Algebra I is incomplete, and Algebra II through Calculus are under construction. (p.s. Actually, the only thing accessible is currently basic multiplication and exponents.) (p.p.s. This is a beta release, so not all of the features specified exist. Any new features will be published here first and then, when I decide to officially release it, I will publish the features to the stable release.)