Moodle has an "algebra filter" which can display mathematical expressions as if they were typeset. The filter is included in the standard Moodle packages but the administrator must activate it before you can use it and it requires that the Moodle Tex filter also be working as the algebra filter simply parses math expressions in one syntax and then converts the expressions to LaTex expressions for the Tex filter to render and display.
More to the point, while it has been argued that the algebra filter is easy to use, there is apparently no Moodle reference on its "grammar" or "syntax". Research in to Webworks produced these two links for using webworks text expressions (the first one is arguably replaced by the second):
* http://webwork.math.rochester.edu/docs/docs/pglanguage/availableFunctions.html * http://webwork.maa.org/wiki/Mathematical_notation_recognized_by_WeBWorK
See http://moodle.org/mod/forum/discuss.php?d=126522&parent=554632 for links to an explanation of this notation from the Webworks site.