How to input mathematical notation

Use the visual and LaTeX math editor
You can click on the math symbol in the toolbar x^2y and compose both inline and new line equations (numbered) both using a visual editor with many math symbols or via a LaTeX math editor with preview. Read more about it here.

Note: to number your equation, select NEW LINE in the equation editor. The number will appear when you quit editing, e.g. when you click on a different part of the document or when you enter preview mode.

Insert equations in a LaTeX block
If you want to write more complex math, insert a LaTeX snippet in your document To insert a LaTeX block, click on Insert -> LaTeX. In the LaTeX block, you can insert an inline formula by typing the equation inside $..$ . For example, type: An inline equation is $e=mc^2$.

To obtain a numbered formula, you need to use the {equation} environment. For example, type:

\label{eq:sedov}
R(t)= A \left(\frac{E_0}{\rho_0}\right)^{1/5}t^{2/5}

Click outside of the LaTeX block (or on another block in the document) to render the LaTeX equation:

If you label it with an eq: label, you will then be able to reference it using the reference tool.