In writing about music, it is sometimes necessary to use musical symbols within the text, as opposed to a musical example that might interrupt the flow of the text. Some of these needs are answered by Music. For longer examples, use <score> tags as described in Score.
Many characters not on the standard computer keyboard will be useful—even necessary—for projects in a non-Latin-alphabet language. This page contains recommendations for which characters are safe to use and how to enter them. There are several ways to enter a special character into wikitext:
MediaWiki uses a subset of AMS-LaTeX markup, a superset of LaTeX markup which is in turn a superset of TeX markup, for mathematical formulae. It generates PNG images by default. Alternatively the MathJax renderer can be used, this uses a combination of HTML and CSS to display the equation, it can be selected in the user preferences.
A wikitable is an arrangement of columns and rows used to organize and position data. Tables are useful for this purpose and there are many different styles and tricks that can be used to customise each. This page gives you information about syntax to build wikitables in Wikipedia.
Wiki markup is the syntax and keywords used by the MediaWiki software to format a page. To learn how to see this markup and to save an edit, see: Editing.