5.22 Reference numbers

Page numbers are usually written in Arabic numerals, but in prefatory material they may be written as lower-case Roman numerals:

• page vii of the Foreword
• page 7 of the Introduction

Within the body of the text, volume numbers may be indicated by Arabic or Roman numerals or be spelled out. Numbers of chapters and other major divisions of a book may be spelled out, but are more often written in Roman or Arabic numerals—the tendency being away from Roman numerals in the case of both chapter and volume numbers. Verse numbers and those of minor divisions of a book are written as Arabic numerals:

• I Kings 9:1–4
• Volume 18, Section 8

Paragraphs may be numbered 1, 2, . . . ; clauses within paragraphs, 1),  2), . . . . Groups of paragraphs may be numbered with Roman numerals. In citations from legislation and the like, numbers and letters designating parts of a section should be enclosed in parentheses, with no space between them:

• subparagraph 123(4)(b)(ii)

See also 4.30 Parts of a book or document.

5.25 Roman numerals

Roman numerals are becoming increasingly rare, but they still have the following uses:

• names of rulers, aristocrats, and the names of ships, racing cars and space vehicles:
  • Charles IV
  • Pius XII
  • Bluenose II
  • Saturn V
• numbers of volumes, chapters, tables, plates, acts and other divisions of a book or play (now often replaced with Arabic numerals):
  • Psalm XXIII
  • Volume XII
  • Appendix III
  • Act II, Scene iii (act number in upper case, scene number in lower case)
    Iliad xi.26
• Government of Canada Statutes:
  • Schedule IV
  • Part III
• years, centuries and recurring events of major importance:
  • CMLXLV (in very formal contexts)
  • XIX century (or 19th century)
  • XXIII Olympiad

Do not use ordinal forms (st, nd, th, etc.) with Roman numerals.

Lower-case Roman numerals may be used for page numbers in preliminary matter (preface, foreword, table of contents, etc.), subclauses and subordinate classifications in a series.

Note that a bar over a letter in a Roman numeral multiplies its value by 1000:

• _
  D = 500 000
• _
  V = 5000

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