This module is displayed in three columns within your browser window.

The contents of the module are arranged in an hierarchical structure in the column on the left of the browser window.

Click on an entry to display the associated page in the centre frame of the browser window. This will also open up any sub-entries there may be. Any other open sections will be closed.

The right-hand column of your browser window displays a control panel, which you will use when you are working with the pages of the module.

Presentation pages and exercise pages

Some pages in the module are presentation pages, that is they present material you should work through and understand. Presentation pages may also contain tables of scores relating to exercises in subsidiary sections, or indices and other information material.

Other pages are exercise pages, that is they help you confirm what you know and discover what you do not know.

• Exercise pages require some kind of input from you and may or may not, depending on the type of the exercise, evaluate that input.
• Exercise pages have a 'scope', which determines what you are expected to know in order to complete the exercise successfully. The scope of an exercise is usually clear from its position in the hierarchical contents list: an exercise that follows a single presentation page will normally concentrate on the material contained in that page; in the same way, an exercise that follows a group of pages will require an understanding of the material in all the pages of that group.

Moving around this module

You can select entries and sub-entries from the left-hand column in any order, and leave or revisit these entries at any time.

The material in the module is organized as a knowledge progression. Later sections assume that you are familiar with the material dealt with in previous sections.

Some pages at the end of the module are indices to the content of the module. This allows you to find pages easily by their titles. A click on an index entry will load that page.