**WIRIS Editor** is a WYSIWYG formula editor designed to streamline the process of writing mathematical formulae. It is a powerful tool that allows composing any math expression with high graphics quality, while remaining simple and easy to learn.

The formulae written have to be placed somewhere; in this section we will describe its use within Moodle, but WIRIS editor is used in other contexts with a minimum of differences.

There are two ways you can open WIRIS editor:

- If you want to modify an existing formula, double click on it;
- If you want to write a new formula, move the cursor to the place you want to write it in, and then click on the icon in the editor toolbar.

After writing or modifying the formula, click on OK if you want to insert the formula as it is shown, or Cancel if you want to exit without saving changes.

Formulae are treated as any other kind of object:

- You can select formulae by either clicking on them or by moving the cursor over them while holding the SHIFT key.
- You can erase formulae by selecting them and pressing delete, or by moving the cursor after (before) them and pressing the delete (supr) key. If you delete a formula accidentally, you can recover it by clicking on the undo icon, .
- You can cut, copy and paste formulae in the usual way, by pressing CTRL-X, CTRL-C and CTRL-V; this is particularly useful when you have to write several formulae which are very similar. You can apply all of those edition operations to a single formula or to combinations of formulae and text, and you can paste to other WIRIS windows.
- Some text formatting functions work with formulae; for instance, if you want to center a formula, select it and click on the icon.