There are several different numbering systems sometimes used in manuals, each with a different purpose:
In modular manuals, the pages aren’t numbered sequentially from the beginning to the end of the manual, so page numbers are not the primary means of locating information. Instead, we number the modules, then number the pages sequentially within each module. In a sectional manual (like this guidebook), the module number and the page number are usually combined (e.g., 3-2). In a 2nd-level manual, the module number is a compound number consisting of the chapter number and the module number (e.g., 5.2). In a 3rd-level manual, the module number is a compound number consisting of the chapter number, the section number and the module number (e.g., 5.2.3).
Some organizations prefer an open numbering system that leaves gaps in the number series for future additions to the manual. Instead of numbering modules 2.3, 2.4, etc, they number them 2.30, 2.40, etc., so that later they can add 2.35 between them. While this strategy provides more flexibility for inserting new modules, it complicates the numbering system.
When typewriters were used to create manuals, authors often used heading numbering to reinforce the hierarchy—each heading in the manual had a number beside it. This was necessary because they couldn’t use other typefaces or type sizes to show each heading’s place in the hierarchy. Now that other typefaces and type sizes are readily available, it’s no longer necessary to use heading numbering.
Some types of documents use a numbering system to number every paragraph. This is common in legal acts and regulations, as well as technical specifications. Its purpose is to make it easy to cross-reference individual paragraphs (e.g., "Notwithstanding Section 4(1)(c), then...") Normally an alphanumeric numbering system is used, which mixes numbers, letters and Roman numerals. Paragraph numbering is seldom used in other kinds of manuals.
Pages in a modular manual are numbered sequential only within a module. When a new module begins, the page numbering starts at page one again. The page numbering is usually separate from the module numbering so they are not confused.
The pages at the front of a manual are usually numbered with Roman numerals (such as ii, iii, and iv). The numbering is considered to start on the title page even though a page number never appears on it or the back of the page, therefore the first number to appear is usually iii.
Because many people are uncomfortable with Roman numerals, some authors like to organize the material at the front of the manual as though it were Chapter 0. The table of contents would be module 0.1, the Introduction would be 0.2, the Index would be 0.3, etc. Page numbering would then be the same as other modules.
Figure numbering is often used in manuals which have a lot of illustrations, tables or diagrams. Figure numbering is usually sequential within each module. For example, in module 5.2, the figures would be numbered 5.2-1, 5.2-2, etc.
