Formatting Tip: Numerals

Posted December 14, 2014 by Kathy Davie in Author Resources, Editing, Formatting Tips, Self-Editing, Writing

Who knew numbers could have so many rules! It begins with the types of numbers — cardinals, nominals, and ordinals and then plunges into number structure. Hah, and you thought number structure was all about 1, 2, 3, 4!

Context, circumstance, and/or whether the number is written or spoken will determine how the number is presented.

Formatting Tips started…

…as my way of dealing with a professional frustration with words that should have been capitalized or italicized, in quotes or not, what should be spelled out and what can be abbreviated, proper styling for the Latin names of plants, the proper formatting and usage of titles and more in manuscripts I was editing as well as books I was reviewing. It evolved into a sharing of information with y’all. I’m hoping you’ll share with us words that have been a bête noir for you from either end. A useful post to bookmark for future reference, consider sharing this style tip with friends by tweeting it.

General Rule: I know this gets really tedious and very mind-numbing. An easy, easy rule could be to simply spell out all arabic numerals 9 and under and use arabic numerals for all arabic numerals 10 and up.

Being consistent is the most important point.


300 = hundreds 20 = tens 7 = units
Post Contents:
Types of Numbers

Styling with Numbers

Use Arabic Numerals Spell It Out
10 through infinity
10, 11, 12, 13…45…109…1,403…

Use arabic numerals in scientific and technical situations.

Use arabic numerals for 101, 5,403, fractions, etc.

Writing out numbers:
U.S. Rule: Only the number; there is no and

one hundred five
one hundred sixty-two
two thousand three
one thousand nine hundred eighty-four

British Rule: Inserts an and before the tens and units

one hundred and five
one hundred and sixty-two
two thousand and three
one thousand nine hundred and eighty-four

Speaking numbers:
U.S.; British:
Inserts an and before the tens and units

AP, APA, Chicago:
Spell out 0 through 9
zero, one, two, three, four, etc.

Numbers at the beginning of a sentence are ALWAYS spelled out. Always. It would be better if you reword the sentence so you don’t start with a number. Well, okay, except if you are doing a text-message dialog.

In nontechnical situations, spell out whole numbers between one and one hundred and round numbers.

If your topic doesn’t use a lot of numbers, spell out numbers that use one or two words, hyphenate two-word numbers:

  • thirty-seven
  • fifty-two
  • one hundred
  • fourteen hundred
  • three-fourths, etc.

You don’t hyphenate the hundreds or thousands.

Three Types of Numbers
Cardinal Number Definition: A counting number, a noun. A number used to count that indicates how many of something there is, is the common usage (Merriam-Webster). If you’re a math geek, then things get much more complicated…and you’re on your own!

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1,984 ++
Nominal Number Definition: A number used only as a name, or to identify something, but not as an actual value or position.

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the eight ball on a billiard table
a phone number: 555-1212
a product number: MV-PV138A4
Ordinal Number Definition: Tells the position of a number

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32nd ++
Ordinal with Letter Rule: Italicize when using a letter in place of a number, but leave the suffix in roman (Chicago, 9.9).

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to the nth degree
Styling with Numbers
Use Arabic Numerals Spell It Out

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A numbered address always:

  • Uses arabic numerals
  • Does not use a comma in addresses
Street names from First through Ninth are always spelled out and always capitalized.
The haberdashery is located at 3809 W. Main St.

I think he said the address was 113493 Handsdown Drive.

The fire was at the corner of Ninth and West Main, but the water main broke at 14th and South Oak.

Send the bill to 4115 W. Fourth Ave.

There is no such address as 718 S. Fifth St!

Use figures for street names over 100.

Building numbers are in arabic numerals UNLESS…

Street names under 100 are spelled out.

If a building number is part of its address, then spell it out.

We’ll have to go over to 135th Avenue.

The menswear store is over on Forty-fifth.

Did you say it was on Ninety-ninth?

One IBM Plaza

Highways Rule: State, federal, and interstate highways use arabic numerals (Chicago, 9.55).

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County LLC
Highway 32
Interstate 94
I 94
Wisconsin 34
U.S. Route 22
U.S. 22
Apartment Number Rule: Use arabic numerals and/or uppercase letters (Chicago).

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She’s in apartment 14C on on 150th Street.
Use Arabic Numerals Spell It Out

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Building numbers.
If the building name is part of the address.
10 Downing Street
1600 Pennsylvania
One World Trade Center
One Microsoft Way
One Thousand Lakeshore Way
Use Arabic Numerals Spell It Out

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AP, APA uses arabic numerals:
Age in conjunction with the phrase “year old” uses two distinctive formats:

  1. As an adjective or noun, always hyphenate
  2. If used as part of a range, three- to nine-year-olds
Never hyphenate when it includes years


  1. Green emphasizes years
In referring to ages of people, use 60s, 70s, 40s, 20s, 100s, etc.

Do NOT use this format for decades.

The 800-year-old vampire was weary of life.

They kidnapped a five-year-old.

I believe Peter’s twenty-one years old today.

Testing was done on women 45- to 60 years old.

That couple is in their 70s.

Alphabetizing Rule: Spell it out IF it’s an isolated item. Yep. There’s numerical sequence, and then there’s alphabetization. Numbers are alphabetized as if they were spelled out.

If there are a series of numbered items, stick with numerical sequence.

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10 Downing Street ten Downing Street
1 Infinite Loop one Infinite Loop
13 Little Blue Envelopes thirteen Little Blue Envelopes
3809 Martin Ave., 4115 W. Main St., 6834 – 127th St., 10119 Lakeshore Drive, etc.
Parts of Books Ebooks are treated the same except where noted.
Appendix Rule: If more than one appendix is used, they should be labeled consecutively with either numbers or letters followed by a unique title.

Ebook: The appendix requires a number and should be hyperlinked.

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Appendix 1 Tables
Appendix 2 Maps
Appendix A …
Chapter Rule: Chapters are always numbered consecutively; to have a chapter, there must be at least two (Chicago, 1.66).

Ebook: The chapter requires a number and should be hyperlinked.

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Chapter 9
Chapter 10
Endnote Rule: Within the text, MLA uses superscript arabic numerals after the punctuation of the phrase or clause to which the note refers.

Ebook: Endnotes should be hyperlinked.

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The theory that Hogwarts does exist can be traced back to Pliny the Elder.3

Since World War II ended, the ignorant have insisted that the Holocaust is a fabrication8—a statement that shows their bigotry.

Designs three through five have some flaws in their stability5; and yet, the design for the new dual-layer bridge in four has some merit.

Endnote List Rule: In the back matter, MLA uses arabic numerals that correspond to the in-text citations. Start with the endnote number, a period, and a space before providing the substance of the endnote. The first line in each note is indented and double-spaced.

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3. See Smithings in his analysis on magic in Ancient Rome.

8. On Holocaust denial, see Niewyk’s The Holocaust: Problems and Perspectives of Interpretation. See also documents at the Center of Contemporary Jewish Documentation; for a contrasting view, see Harry Elmer Barnes.

5. Several studies on best-practices endorse the stability benefits in this design. See HNS 780.04(5),06; Schneider 14:23.5; Tallings, Friestner, and Allens 34-43.

Footnote Rule: Always use arabic numerals for footnotes and always place the footnote after the ending punctuation.

Also see rules on Superscript & Subscript.

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Becky Burckmyer has useful information in her book, Awesome Grammar. 1
Front Matter Rule: Generally use lowercase Roman numerals.

Ebook: Due to the different display sizes of eReaders and readers who change font sizes, page numbers are irrelevant and hyperlinks are better used.

Ebook: Due to the different display sizes of eReaders and readers who change font sizes, page numbers are irrelevant.

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i, ii, iii, iv, +++
Pages Rule: Page numbers use arabic numerals for the most part and begin after the front matter, continuing consecutively through the book. Do not use a comma on 4-digit-and-up numbers. See also Front Matter regarding front matter pages and Volume regarding pagination for multiple volumes.

Ebook: Due to the different display sizes of eReaders and readers who change font sizes, page numbers are irrelevant and hyperlinks are better used to locate chapters, figures, tables, etc.

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1, 2, 3, 4, 5 … 1512
Paragraph Number Rule: Generally used in a technical manual which undergoes annual (or more frequent) revision, it is more practical to use a paragraph number as opposed to a page number.

Ebook: Use hyperlinks.

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The Chicago Manual of Style uses paragraph numbers such as “18.12 Locators” to allow the cross-references to remain the same throughout different editions.
Part Definition: A book may be divided into parts, each of which must contain at least two chapters. Part numbers and chapter are consecutive.

Rule: Generally uses arabic numerals.

Form: Part #: Chapter Title

a.k.a., section

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Part 2: Word Confusion Endings
Section Rule: If a section is cross-referenced from elsewhere within the book, it should be numbered using double or multiple numeration, i.e., begin with XX.1 with each new chapter or XX.xx.1, etc., with each new subsection or lower. This is extremely useful in scientific or technical books.

Ebook: The section still requires a number and should be hyperlinked.

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Volume Rule: Use roman numerals or spell out the number. BUT if using the volume number in documentation, use arabic numerals.

Documentation Form: vol. XX
#:## (volume:page number) See also Volume

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Volume One
Volume V
vol. 12
Volume Pagination Rule: If there is more than one volume, pagination may continue on from volume one or may begin anew. If an index regarding both volumes will appear in the second volume, it’s best to continue pagination (Chicago, 1.105).
Types of Books Certain types of books use numbers in a specific manner.
Bible Rule: References to passages in the bible are always in arabic numerals. Use a colon to separate chapter and verse with no spaces between.

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Genesis 1:1
Exodus 20:3-17
Psalm 23:1
Proverbs 3:5
1Corinthians 13:13
Play or Poetry Rule: Use arabic numerals when referring to divisions within a play or poem. Also see Capitalization for those rules about plays or poems.

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act 4, part 22, line 12
canto 2
stanza 5
Use Arabic Numerals Spell It Out

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nineteenth century
eighth century
twenty-first century
fourteenth century A.D.
Date Definition: A date is the month and day OR the month, day, and year.

Rule: Uses either arabic numerals or they are spelled out.

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Use Arabic Numerals Spell It Out
July 4
September 1
fourth of July
first of September
All-Numeral Dates
Use Arabic Numerals Spell It Out
Casual use only.

Recommends an all-numeral style, year-month-day. Chicago notes that this does make sorting easier.

Spell it out in full in formal writing UNLESS being used in documentation or tables.

Chicago, 9.39

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[U.S.] 8/11/36

[British, Australian, European] 11/8/36

August 11, 1936
Aug. 11, 1936
11 August 1936
11 Aug. 1936
Use Arabic Numerals Spell It Out

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NEVER use -st, -nd, -rd, or -th with arabic numerals UNLESS a specific date is mentioned. While people may “speak” an ordinal when talking about a date, the print version is always a cardinal number (Skillin, 129; Chicago, 9.35).
Use -st, -nd, -rd, or -th with a spelled-out number after the date (Skillin, 129)

A day mentioned without the month or year is treated as an ordinal and spelled out.

July 2, 1943
Dec 12

May 1st
October 8th

Her birthday was on August 11, but her gift didn’t arrive until the twenty-fifth.
Placement CAUTION: This particular usage depends upon your target reading audience and not the setting. You want your reader to subconsciously understand the date, not have to stop and work it out.

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[U.S.] January 28, 1943
[British, Europe] 28 January 1943, a.k.a., little endian form
[Europe] 1943 January 28, a.k.a., big endian form

  • Short Numerical Rotation: 28/1/43
  • ISO Standard: 1943-1-28

[Hungary] 1943. január 28

Use Arabic Numerals Spell It Out

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Do not use an apostrophe between the year and the s.

Use arabic numerals if using a 4-digit year and do not use an apostrophe.

WIT: (Skillin, 128)
Prefers an apostrophe with a four-digit decade.

Spell it out if the century is clear.
the nineties

class of ’98
spirit of ’76
gold rush of ’49
First Two Decades
of a Century
Rule: The first two decades of any century are not treated in the same way as above (Chicago, 9.37):

  • 1900s is interpreted as referring to the whole of the twentieth century
  • The 10s or 1910s is confusing while the teens is awkward and inaccurate: 1913 to 1919 does not encompass the actual time which would be 1910 to 1919 OR 1911 to 1920

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Chicago suggests:
the first decade of the twenty-first century, or

the years 2000-2009

the second decade of the twenty-first century, or

the years 2010-2019

2-Digit Year Rule: If you abbreviate the year down to two digits, use an apostrophe to indicate the two missing numbers.

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the San Francisco Earthquake of '06
4-Digit Year Rule: In general use arabic numerals; spell it out if the year starts a sentence.

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Use Arabic Numerals Spell It Out
In 2015,
The year, 1776, was the year in which…
Seventeen hundred and seventy-six was the year in which…

Eighteen hundred and fourteen found…

5-Digit ++ Year Rule: For years with five or more digits, use a comma. Be sure to use A.D. before the year unless the year is spelled out,, and B.C. after the year.

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42,000 B.C.
A.D. 907
2000 B.C.
25,495 B.C.
tenth century A.D.
69 B.C.
Range of Years Rule: When indicating a range (use an en dash), you,may drop all but the last two digits providing the first two are the same (see also inclusive numbers):

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Comparing Numbers
Numbers 9 and Under Rule: Spell it out.

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Use Arabic Numerals Spell It Out
  • one-man invasion
  • the fourth of five dates
Numbers That Include 0-9 AND 10 and Up Rule: Use arabic numerals if using both single-digit and multiple-digit numbers.

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Use Arabic Numerals Spell It Out
7 out of 10 doctors agree

Lines 9 and 32

5 of the 18 books focus on

the clothes she packed included 2 handbags, 3 belts, and 14 pairs of shoes

the 20th time we went out was even more passionate than the 1st

Not Being Compared Rule: See General Rule on arabic numerals or spelling it out.

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  • 14 different tiles in three different bathrooms
Use Arabic Numerals Spell It Out

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AP Stylebook:
Use arabic numerals in reference to distances.

Arabic numerals are used in a scientific context.

Spell it out.
It was a 35 km test.

We’ll need to use a 240-volt outlet.

Oh, aye, it was three mile to get to school in my day, uphill all the way.

Oh, that was nothing. I had to walk five miles to school with half of it up a five thousand foot mountain.

Government & Organizations Rule: When referring to governments, dynasties, congresses, other governing bodies, military units, places of worship, political and judicial divisions, etc.

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Use Arabic Numerals Spell It Out
When over 100, use the number + -st, -nd, -rd, or -th
When under 100, use ordinal numbers and spell them out
101st Airborne Division
114th Congress
First Continental Congress
Third Baptist Church
Twelfth Ward
Eleventh Dynasty (of the Middle Kingdom)
Fifth Army
Lodges, Unions Rule: Local branches of labor unions and fraternal lodges use cardinal arabic numerals.

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U.S. Rubber Local #22
IA Local 8
North Branch Masonic Temple 312
Math Equation
Rule: Number using arabic numerals only if they are referred to in the text and they would not be easily identifiable any other way.

Illustrations and figures are numbered consecutively from the beginning OR use double numeration, i.e., chapter number and figure number AND be consecutive within each chapter (Skillin, 264).

The benefit of beginning from xx.1 in each chapter is the easier renumbering if you end up adding another illustration or figure in chapter 3 when you’re already up to chapter 12 and there are fifteen of ’em between the chapters!

And if a figure, illustration, or other images are added so late that it’s a nightmare to renumber everything, then resort to using letters.

Ebook: If any illustrations (this includes plates, figures, maps, charts, etc.) are not the same in both the print AND the eBook, each category must be numbered separately in both versions. In an eBook, each should be hyperlinked.

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Figure 2
Fig. 15.3
Fig. 4
Figure 12.3
Ill. 10.8
Fig. 4A
Caption Rule: With a caption, the identifying number is sometimes ended with a period and a space before beginning the caption text. Sometimes even the word figure or plate is omitted using only the number and a period (Chicago, 12.34).

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Fig 12. Holly Nails Mexican Food, April 1996

Figure 3.1. Skating on the lagoon

Plate 5 Cherry Blossom Festival in Tokyo

3.1. Skating on the lagoon

Figures in Parts Rule: If parts of a figure are referenced in the text, letters may be used.

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fig. 7B
fig. 13D
fig. 8a
Gallery Illustrations Rule: Illustrations grouped together in a block are not numbered unless they are referenced within the text, and then they are numbered separately from figures, plates, etc., within the text.

IF illustrations and plates are mixed in the gallery group, they must be sequenced separately.

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Fig. 2 (in the text, use fig. 2)
Plate 2 (in the text, use plate 2)
Inclusive Numbers Definition: Includes the first and last number and all numbers in between.
When to Use En Dash Rule: Using an en dash between two numbers means that the reader should read it as from this first number up to and including or through this last number (Chicago, 9.62).

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The color photographs are on pages 145–167.

We’ll need to look at your tax returns for 1999–2004.

You may not ride this ride if you are 0–12 years of age.

Don’t Use En Dash Rule: If using or implying from or between, do not use an en dash. Instead use a combination of either from + to OR from + through OR between + and. If you need to be precise, use one of the froms (Chicago, 9.63).

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I think she’s between 25 and 30.

It happened between 1996 and 1999.

The Lotus went from 0 to 120mph in twenty seconds.

The ice cream parlor was open from 10 a.m. through 10 p.m.

Spelled-Out Numbers Rule: If numbers are spelled out, do NOT use an en dash (Chicago, 9.63).

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You may not ride this ride if you are zero to twelve years of age.
Abbreviate or Condense Rule: Mostly used with page or serial numbers because they don’t use commas, this style emulates how someone would read the numbers aloud (Chicago, 9.64).

There are four different patterns in the style preferred by Chicago:

  1. Use all the digits if the numbers include 1 through 99 AND a “100” or multiples of the “100”
  2. For 101 through 109 (201 through 209, 301 through 309, etc.), use only the changed part
  3. For 110 through 199 (210 through 299, 310 through 399, etc.), use two more digits as required
  4. Four-digit numbers use all four digits IF three digits change

Other styles require including all the digits on either side of the through, and, or en dash.

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Read pages 10–69.

Read pages 1100–1117.

Read pages 405–9.

Read pages 378–99.

Read pages 1001–1115.

Use Every Single Digit if… Rule: Vote tallies, sports scores, etc., are not indicative of a range, so you must use every digit (Chicago, 9.65).

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The vote tally was 24,301 to 23,999.

The score was 38 to 20.

If Using Commas Rule: Repeat numbers to the right of the comma as needed (Chicago, 9.66).

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Inclusive Years Rule: Chicago uses an adaptation of the patterns in abbreviated or condensed with a few guidelines (Chicago, 9.67 and 9.64).

It essentially boils down to your using as many digits as are changed, although you should still use all four digits if three digits change.

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Judgment in Death takes place in the winter of 2058–9.

Augustus, the Roman Empire’s first emperor, ruled from 27 BCAD 14.

The Cambrian period lasted from 541.0–485.4 million years ago.

Inclusive Years in Titles Rule: In book titles, the custom is to repeat all four digits (Chicago, 9.68).

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Eric J. Hobsbawm wrote The Age of Extremes: A History of the World 1914–1991.

Gordon S. Wood’s Empire of Liberty: A History of the Early Republic, 1789–1815 is fourth in the Oxford History of the United States series.

Inclusive Years within Books Rule: Inside a book, it is acceptable and appropriate to shorten the inclusive years per the above rules for (Chicago, 9.68):

  • Chapter titles
  • Subheads
  • Table titles
  • Figure captions

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In chapter 10, “From Coal to Diamonds, 1874–88

Fig. 15–30. Selected works by Rembrandt van Rijn, 1620–35.
Table 7. Analysis of Books Read, 2004–11

Legal Rule: Primarily use arabic numerals, although both arabic and roman numerals may be used to tell the difference between divisions.

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We’ll have to file for Chapter 11.

Have you invested in a 401(k) yet?

You should check out paragraph 4(vii) in the bylaws.

Article II, Section 4 OR article 2, section 4

Amendment 64 made the personal use of marijuana legal in Colorado November 6, 2012.

The Fifth Amendment (or Amendment V) gives us the right to remain silent to protect ourselves from incrimination.

List Rule: There are two types of lists: a run-in and a vertical. A list that uses numbers or letters is referred to as an ordered list.

Chicago: Use arabic numerals for an ordered list.

Also see Outline under “Roman Numeral”.

Chicago; Capital Community College Foundation.

Run-in List Definition: A list that is part of a sentence.

Rule: Use enclosing parentheses around the numbers, no period, and a semicolon to separate the list items.

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The cover for a book has three parts: (1) the front; (2) the back; and (3) the spine.
Vertical List Definition: List items are indented with each item on its own line; subdivided items are indented further to help distinguish them from the upper level.

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Chicago: The first level uses arabic numerals with the second level using lowercase alpha. Punctuation-wise, use a period and a space for the first three levels; use single or double parentheses for the next four levels. Text for a line item that overflows to a second line must line up with the first letter of the line item.

A.k.a., display list, HTML & CSS refer to a subdivided list as nested

1. Numerals
a. Address
b. Book
i. Anatomy of a Book
1) Chapter
(a) Section
i) Subheading
2) Sub-subheading
2) Page
2. Time
List of Four or More Numbers Rule: Always use arabic numerals.

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in row 6
1, 5, 7, and 9 words
In General: Use arabic numerals when mathematical functions are involved. Also see Illustration for details on numbering mathematical equations in a book.
Decimal Rule: Include a 0 and a decimal point in front of numerals that are less than 1 to ensure the reader reads it properly.

When used in a table, the 0 in the 0.xx can be eliminated unless required by the publisher.

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Decimals Omitting 0.xx Rule: An exception to the 0 rule is when the quantity is always less than 1.00, as used in probabilities, correlation coefficients, etc., and the 0 is left off AND in baseball batting averages and firearm caliber (Chicago, 9.21).

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.22 caliber
He used a .357 Magnum.
Ted Williams of the Boston Red Sox hit .406 in 1941.
Use Arabic Numerals Spell It Out

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Use arabic numerals for mixed fractions.

Do not use th or ths after an arabic numeral.

Spell out simple fractions and use hyphens unless the fraction is open.

We each got a quarter of the pie.

I love Joanne Harris’ Five Quarters of the Orange.

Rule: Do not use of a or of an after an arabic numeral.
¼ inch
¼ of an inch
one-quarter of an inch
Whole Number with Fraction Rule: If the combination is short, spell it out, but all numerals is usually better.

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College essays have to be on 8½ x 11-inch paper using a 12-point New Times Roman font.

I’ll need 7½ yards for the skirt I like.
My sister is 5 feet 10¾ inches tall.

Oh, well, aye, my sister and I had to walk ten and one-quarter miles through freezing rain to get to school.

I only need a half yard of that fabric.

Measure-ment Rule: Use arabic numerals immediately before a unit of measure and spell out feet, inches, yards, etc.

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Uses Arabic Numerals Spell It Out
2.5 cm
.50 caliber
2″ by 4″
Prefers arabic numerals for physical quantities in scientific contexts and when abbreviations or symbols are used.
Generally prefers that numbers are spelled out.
2.5 cm
.50 caliber
120 square feet
3.5 L
15 hectares
30 g
8 h
35 mm film
75 mph
six feet
six foot
Abbreviations & Symbols with 2+ Quantities Chicago uses the symbol or abbreviation:

  • For each number if the numbers are closed up
  • Once for the “phrase” if the numbers are separated

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Closed Up Separate
2″x4″ 2 x 4″
25%–68% 25 – 68%
10°C–25°C 10° – 25°C
As an Adjective Rule: When numbers are used as a simple adjective, use arabic numerals and spell out the measurements.

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Uses Arabic Numerals Spell It Out
Mandy is 4 feet 7 inches.

Chicago, exceptions:
I prefer a 16-point font size on a website.

Mandy is four feet seven inches.

Oh, that was nothing. I had to walk five miles to school with half of it up a five thousand foot mountain.

Rule: When numbers and measurements are used as an adjective in front of a noun, use hyphens between the arabic numerals and the measurements.

  1. Green indicates the measurement used as an adjective
  2. Blue indicates the noun being modified
  3. Pale Green indicates the simple adjective

Mandy is a 4-foot-7-inch waitress.

They used 2-by-6 framing in their house.

The bedroom is 14 feet by 16 feet with an 8-foot ceiling.

Use Arabic Numerals Spell It Out

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When an amount of money includes dollars and cents, use arabic numerals. This applies to any foreign currency as well.
When the amount is only dollars or only cents, it can be spelled out. This applies to any foreign currency as well.
£5 25s. 3d.
R 10
ten dollars
fifty-five cents
thirty-five bucks
forty-three pounds
sixty-seven euro (or euros)
ten rand
Rule: If one of the “dollar” amounts is only cents, be sure to include a 0 and a decimal point in front of the cents to ensure clarity.
Rule: Do include .00 for even dollar amounts when dollar-only amounts are noted along with dollar + cent amounts for consistency and to ensure that no one thinks you’re embezzling(!) from your story.
Rule: When including U.S. dollars and currency from countries which also use a $ sign, the country must be identified.
three hundred Canadian dollars
five hundred fifty New Zealand dollars
Mex$45 forty-five Mexican pesos
sixty-five Australian dollars
BSD $105 One hundred five Bahamian dollars
Rule: In an informal financial context, thousands are sometimes represented by K (Chicago, 9.28).
The POS went for $1K.
Movie Title Rule: When referring to a sequel to a movie, use Roman numerals (Chicago, 9.48).

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Rocky IV
Mission Impossible V
Shrek II
Numbers that are Side-by-Side Rule: When combining different number units in one sentence, alternate between arabic numerals and spelling it out (Burckmyer, 192). Chicago (9.7) suggests using the same format for each category within a paragraph or series of paragraphs.

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I’ll need thirty-six 0.5-inch bolts for the bookcase.

I’ll need 36 half-inch bolts for the bookcase.

Be consistent by using a spelled-out number for all quantities and an arabic numeral for all numbers that measure. Or vice versa.

I’ll need 36 0.5-inch bolts for the bookcase.
She had 10 hundreds sewn into her hem.

She had ten 100s sewn into her hem.

Be consistent by using a spelled-out number for the names of the bills and an arabic numeral for the quantities. Or vice versa.

She had 10 100s sewn into her hem.
Percentage Definition: An absolute rate, number, or amount in each hundred.

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Use Arabic Numerals Spell It Out
Rule: Technical & scientific writing uses arabic numerals. In a table, always use %.

Always give percentages in arabic numerals with % in scientific and statistic contexts with no space between the number and the symbol. Also in humanistic copy that includes a lot of percentage arabic numerals.

Rule: If the context is not scientific or technical, spell out the number and percent.


7 percent
100 percent
seven percent
Rule: Always use a decimal, never a fraction. Be sure to include a 0 in front of a percentage that is less than 1.00, especially if other percentages are whole numbers. If the numbers are all less than 1.00, the 0 can be eliminated.
3.25 percent, not 3¼ percent
0.25 percent, not ¼ percent
Percentile Definition: References statistics:

  • Each of the 100 equal groups into which a population can be divided according to the distribution of values of a particular variable
  • Each of the 99 intermediate values of a random variable that divide a frequency distribution into 100 groups

In General: Use arabic numerals.

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Your baby is within the tenth percentile for weight for his age.

You had a percentile of 86 which means you scored better than 85% of those who took the test.

Pluralizing Numbers Rule: Style guides differ, so go with the style guide you are using. And be CONSISTENT.

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With Arabic Numerals Spell It Out
We’ll need twenty 4 x 4s
She was in her 20s.

She was born in the 1970s.

We’ll need twenty 4 x 4’s
She was in her 20’s.

She was born in the 1970’s.
(Skillin, 478)

The camp was at sixes and sevens.

Tens of thousands
Count by fives to fifty.

Physical Quantity Rule: Chicago uses a combination of arabic numerals and spelled-out numbers depending upon common usage and commonsense.

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Use Arabic Numerals Spell It Out
Chicago, exceptions:
Honey, pick up some 75-watt bulbs, will ya?

Can you believe she claims to wear a size 2 dress?

Her car only gets 15 miles per gallon.

The temperature rose thirty degrees in three hours!

Pick up five hamburgers and ten pies, Pete.

Points on a Scale In General: Always use arabic numerals.
Punctuation Rule: Where and when to use a comma varies depending upon regular use or scientific use, American and British common style versus Canadian versus the International System of Units (more common amongst science, medicine, government, and various fields of technology and engineering fields), type of usage, and more:

America vs International System of Units Rule: In general, numbers are separated into three-digit units using decimal points and commas. How they’re separated is different among American, Canadian, European, and the International System of Units (SI).

Common use in America and Great Britain is a:

  • Comma to separate every three digits to the left of a decimal point
  • No commas to the right of a decimal point

Common use in Canada is a:

  • Space to separate every three digits on either side of a decimal point

Common use in Europe is a

  • Space to separate every three digits on either side of a comma which takes the place of an American decimal point

SI is metric and uses a:

  • Space between every three digits, BUT
  • A 4-digit number does not use a space — on either side of a decimal point

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American Common Canadian European SI (metric)
157 157 157 157
1,000 1000
2,500.98403 2500.98 403 2500,98 403 2500.98 403
3,425,199 3 425 199 3 425 199 3 425 199
298,456.3987 298 456.3987 298 456,3987 298 456.3987
Possessive Numerals Definition: Relating to a word or a form of a word that shows that something or someone belongs to something or someone else.

Rule: Ownership or possession is usually shown by the use of an apostrophe s (‘s).

CAUTION: Do not confuse a plural number with a possessive number.

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Hurricane Katrina was 2005’s eleventh named storm and its fifth hurricane.
Quartile Definition: A type of quantile, it references descriptive statistics in which the quartiles of a ranked set of data values are the three points that divide the data set into four equal groups, each group comprising a quarter of the data.

When such statistics are applied in the fields of epidemiology, sociology and finance, the quartiles of a ranked set of data values are the four subsets whose boundaries are the three quartile points.

In General: Use arabic numerals.

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This response is in the upper quartile.
Ratio In General: Always use arabic numerals and either a colon to express the relative sizes of two or more values — there is no space before or after the colon — or a to with space between the to and the numbers.

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With a Colon In Words
For freenetname broadband, the contention ratio is 50:1, meaning that there are 512kbps of download bandwidth available for every 50 users. For freenetname broadband, the contention ratio is 50 to 1, meaning that there are 512kbps of download bandwidth available for every 50 users.
Native 16:9 aspect ratio is ideal for watching the latest blockbusters. Native 16 to 9 aspect ratio is ideal for watching the latest blockbusters.
Roman Numeral In General: Roman numerals use upper- and lowercase letters: I, V, X, L, C, D, and M. In arabic numerals, this would correspond to 1, 5, 10, 50, 100, 500, and 1,000.

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Repeating a letter repeats its value: X = 10, XX = 20

Place a smaller-value letter in front of a higher-value letter, and it reduces the value of the higher-value: XL = 90, or 10 – 100.

Place a higher-value letter in front of a lower-value letter, and it increases the value of the combined letters: LX = 110, or 100 + 10.

A line (macron) placed over a letter adds three 0s to it: V̄ = 5,000; C̄ = 100,000; M̄ = 1,000,000

Musical Chords Rule: Use uppercase Roman numerals to identify major triads in the root position of musical chords (Alcorn State University).

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Displays triads in the key of C major

This “example from Alcorn State University shows how triads in the key of C major are identified with roman numerals. Notice that I, IV, and V are major; ii, iii, and vi are minor; and viio is diminished.”

Rule: Use lowercase Roman numerals to identify minor triads in the root position of musical chords (Alcorn State University).
Displays diatonic triads in melodic minor

This example shows “diatonic triads in melodic minor”.

Outlines Rule: Chicago: Use uppercase and lowercase Roman numerals as part of an outline. This also applies to lists.

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I. Numerals
A. Address
B. Book
1. Anatomy of a Book
a) Chapter
(1) Section
(a) Subheading
i) Sub-subheading
b) Page
II. Time
Proper Names & Rulers Rule: Use uppercase Roman numerals to separate monarchs, popes, and family members with identical names. Do not use commas to separate the name and the Roman numeral.

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Louis XIV
Pope John Paul II
Richard Wilmington Brown IV
Front Matter for a Book See Front Matter under “Book”.
Rounded or Approximate Numbers
Under a Million (Burckmyer, 192)

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I believe there are about 30 thousand students enrolled.

It looked as if about two hundred or so infantry units were on the beach.

Greater than a Million Rule: For numbers greater than a million, it is written as both a arabic numeral and a word (Burckmyer, 192; Chicago, 9.10).

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It’s estimated that people have been on earth for 5 million years or more.

Geological data on the Arctic Ocean indicate 400 billion barrels of oil.


  1. Green indicates the arabic numeral + word phrase
Billion Traditional Definition: (Chicago, 9.10)
[U.S.] thousand million
[British] million million, a.k.a., trillion

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15,000,000,000, etc.
Sample, Subsample, Population Size In General: Always use arabic numerals.
Scoring & Votes In General: Use an en dash between the arabic numerals with no spaces. Never spell out the numbers; always use arabic numerals. The winning score is always listed first.

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With an En Dash In Words
The match ended in a 64–54 split.

The game was close at 45–44.

It was a close vote at 1,928–19,25.

The score was Green Bay 22, Tampa 15.

The count was yeas 54, nays 32.

Specific Place in a Numbered Series In General: Always use arabic numerals.
Specific Numbers of Subjects / Participants in an Experiment In General: Always use arabic numerals.
Superscript & Subscript Definition: Superscript and subscript are smaller numbers that are set higher or lower to the baseline and in a smaller font than is used in the text.
Superscript Rule: A superscript is a number, arabic numeral, symbol, or indicator that is placed high to the baseline with a smaller font-size and are used for chemical symbols, mathematics, footnotes, intellectual property symbols, etc.

Note the ending punctuation placement.

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Bibliographic references: Skillin1, 2
Exponents It’s always been 43.
Footnotes. See Skillin’s book. 3
Mass number of isotopes: 14C
Intellectual property: Coca Cola ®
Subscript Rule: A subscript is a number, arabic numeral, symbol, or indicator that is placed at or below the baseline with a smaller font-size and are used for chemical symbols, mathematics, computing, etc.

Note the ending punctuation placement.

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Base for a number system: 2510
Numbers of atoms in an element: That’s pure H2O, buddy.
Table Number Definition: Refers to the practice of numbering tables in a book.

Rule: Always use arabic numerals for a table number; do label the tables in your book consecutively from the beginning OR use double numeration, i.e., chapter number and table number AND be consecutive within each chapter.

The benefit of beginning from xx.1 in each chapter is the easier renumbering if you end up adding another table in chapter 3 when you’re already up to chapter 12 and there are fifteen tables between the chapters!

Typographically, the table number can be the same size as the table title and the table body. Or larger. It can be in a different font style from the table title.

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Table 1. Lexical Verb Forms

Table 1.14
Table 3.7
Table 4
Table 8

Column Number Rule: If a column numbers is referenced within the text, it must be numbered with arabic numerals in parentheses and centered immediately below the column head.

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Book Type Binding Modern Cover Size
in inches
Page sizes are usually 1/4″ smaller
Good For
(1) (2) (3) (4)
Trade paperbacks
Octavo or crown octavo
Paper, better quality paper and binding Usually the same size as the hardcover.

6 x 9

5.12 x 7.8 (Known as “B” format)

Most modern digest magazines

Priced between mass market and hardcover books.
Mass market paperback
Known as “A” format (16mo)
Paper 4.33 x 7.01
4.25 x 7
4 x 6.75
Cheaply made and

point-of-purchase in grocery stores, airports, drugstores, etc.
Telephone Number
North American Rule: North American telephone numbers follow a three-three-four format, i.e., 555-123-4567, with the first three numbers representing the area code.

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(555) 123-4567
International Rule: International telephone numbers should include the country code using the plus format.

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+1 (555) 123-4567
+44 12345 678 912
Use Arabic Numerals Spell It Out

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Always use arabic numerals with a colon to separate hours from minutes.

CAUTION: Never use :00, instead format it as 4 p.m.

9 p.m.
four o’clock

We’re meeting at half past four.

We have to leave at quarter to four.

We got in at a quarter after four.

Dude, it’s beer thirty.

If using precise time in a story, apply the above rules regarding arabic numerals, colons, :00, and noon and midnight.
2 p.m.
9:36 p.m.
Let’s get lunch at 1200.

The attack is set for 2400.

Let’s get lunch, it’s almost noon.

Prefers arabic numerals for units of time in scientific contexts.

Do use :00 if specifying exact times (Chicago, 9.41).

Generally prefers that numbers are spelled out, especially with o’clock.

Time may also be spelled out on the quarter, half, or whole.

9:00 p.m. I can’t believe it’s five already.

We have to leave at quarter to four.

We got in at a quarter after four.

Dude, it’s beer thirty.

Rule: Spell the time out using a space between hour and minutes instead of a hyphen.
four fifteen
Rule: If used as an adjective in front of a noun, spell it out.
a four-fifteen bus
I want to catch the three-forty movie.
Rule: Using o’clock requires that time be spelled out.
seven o’clock
ten o’clock
Rule: Always spell out noon and midnight UNLESS using military time.
Meet me there at noon.

Ooh, it’s almost midnight, the witching hour.

Ante Meridiem,

Post Meridiem

Definition: Ante meridiem stands for a.m. while post meridiem stands for p.m..

Rule: As for the am and pm, the U.S. prefers a lowercase a.m. / p.m., the British prefer an uppercase A.M. / P.M., and Europe and the military, prefer to use military time.

CAUTION: Never use a.m. or p.m. with morning, afternoon, evening, night, or o’clock.

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4:01 a.m.
12:38 p.m.
9 p.m.

[U.S.; Chicago] 4:15 a.m.
[Chicago] 4:15 AM (no periods)
[Britain] 4:15 A.M.
[Europe; military, a.k.a., 24-hour system] 1640 or 16:40
[Chicago: Military] 1640 (no colon)
We will attack at 1433 h.
We will attack at 1433 hours.
Detailed Military Time Rule: To include minutes and seconds, use either a colon or a period. If a date is used, use ISO format (Chicago, 9.45).

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06:30:15.3 30 minutes and 15.3 seconds after six a.m.
2001-08-15-18:25:17.9 August 15, 2001 at 25 minutes and 17.9 seconds ater six p.m.
Time Zone Rule: In general, when writing, place the acronym for the relevant time zone in parentheses (Chicago, 15.44; Time & Temperature). If speaking, spell it out (Time & Temperature).

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The class will begin at 3 p.m. (MST).

Our surfing class begins at 5 a.m. (PDT) on the dot.

The bombing run ended at 3:45 p.m. (GMT).

The newscaster said the hurricane was set to hit at 8:15 a.m. Eastern Standard Time.

UTC Definition: UTC stands for Coordinated Universal Time and begins at Greenwich (GMT) which is UTC+0 (Time & Temperature). UT stands for Universal Time.

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Rule: Time zones are noted with a – or + to indicate how many hours behind or ahead of Greenwich Mean Time that zone is (Greenwich Mean

CAUTION: There are exceptions, which are noted on Greenwich Mean

Pacific Standard Time (PST) is eight hours behind which can be abbreviated as UTC-8.

We should arrive in Australia at 10 a.m. (GMT+8), or eight hours ahead of Greenwich Mean Time.

Don’t forget that South Africa is GMT+2 while Chicago is GMT-5, which means I’ll be seven hours later than you. So don’t call after 5 p.m. Central Standard Time.

Military Time Zone Definition: Military time zones are used worldwide for both military and civilian purposes. They represent each of the twenty four time zones in use around the world, including Coordinated Universal Time (UTC) which is represented by the Zulu Time Zone, a.k.a., UTC+0, Greenwich Mean Time.

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These codes are currently used by most military organizations, the International Civil Aviation Organization (ICAO), International Telecommunication Union (ITU), International Maritime Organization (IMO), and the Federal Aviation Administration (FAA) with some slight variations (Time & Temperature).

Rule: Military time zones use the alphabet:

  • Greenwich is Z, or GMT+0
  • East of Greenwich, uses A through M, or GMT+1 through GMT+14
  • West of Greenwich, uses N through Y, or GMT-1 through GMT-12
UTC-3: P is the military time zone for Brasilia, Brazil; Buenos Aires, Argentina; and, Georgetown, Guyana.
Speaking Military Time Rule: Movie characters say “oh six hundred” while military personnel say “zero six hundred”. Always use “hundred” and never “thousand”. Minutes use the same general rule as numbers: fifteen, forty-seven, etc.

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0600 zero six hundred
1000 ten hundred
0415 zero four fifteen
1835 eighteen thirty-five
0016 zero zero sixteen
1300 K thirteen hundred Kilo
2120 L twenty-one twenty Lima
Boat Rule: Boats and such use a Roman numeral.

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Daisy III
Tredding Water II
HMS Carrick II
Spacecraft Rule: Uses arabic numerals.

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Mariner 9
Vostok 1
Saturn V
Explorer 18

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