5 Number Problems

By Mark Nichol

1. Number Collisions

In the sentence “The day the slain woman was to turn 28, 3,000 gathered at a church to recall her life,” the proximity of her age (assuming it is styled numerically rather than spelled out) and the number of mourners confuses the eye. Readers may assume, before they comprehend the sense of the sentence, that the comma after her age and the following letter space are erroneous and that the digits belong in one figure.

If the numerical style for the age is correct, revise the sentence to read, “The day the slain woman was to turn 28, several thousand people gathered at a church to recall her life.” (This distraction can also occur when a year, a room or building number, or any other numerical designation precedes a figure.)

2. Number Ranges

Do not use the word from preceding a number range in which a dash (or, in this case, as employed often in newspapers and online, a hyphen) appears: “The Korean War lasted from 1950-1953” should read “The Korean War lasted from 1950 to 1953” or “The Korean War lasted 1950-1953.” “The class will be held from 7-10 p.m.” is correctly expressed “The class will be held from 7 p.m. to 10 p.m.” (the first p.m. may be elided) or “The class will be held 7-10 p.m.”

3. Number Names

When you employ specialized terms that include combinations of numbers or numbers and letters, be sure you’re typing them correctly. The term in “It’s safe to open your 401K statement again” is correctly rendered 401(k). The designation for a certain nonprofit corporation sometimes incorrectly styled 501c3 or 501(c)3 should appear as 501(c)(3).

4. Numbers with Hyphenation

I’ve written about hyperhyphenation and hypohyphenation before (search this site for “hyphens” for more posts on the topic), but these twin troubles persist, so I will, too: Pay attention when using hyphens in phrases involving numbers. No hyphens are necessary in “The electrified fence is 10-feet-high,” because “10 feet high” is a simple description, not an adjectival phrase describing a noun that follows immediately (“10-foot-high electrified fence” is correct).

One of those extra hyphens can be donated to the phrase “21-year old world record,” which refers not to an old world record consisting of 21 years (is that “old world,” as in “old-world charm”?), but to a world record that is 21 years old.

5. Numbers and Currency

Take care when making references to money: Redundant references such as “The fine was set at $5 million dollars” or “I found $100 bucks in an old shoe box” are common. Be consistent in one article or book about whether you use currency symbols or spell the terms out; the determination should be based on the level of formality (currency terms are usually spelled out in more formal writing) weighed against the frequency of occurrence (numerous and/or technical references to money are best presented with symbols).

Keep in mind, too, that use of the dollar sign is ubiquitous, but the cent sign is rare, so if reference is made separately to dollars and cents, it’s best to spell out both terms: “In 1960, the candy bar cost 5 cents; by the beginning of the twenty-first century, it sold for a dollar.”

Also, avoid using numerals for orders of magnitude. The figure in “The binary star is more than 57,000,000,000,000 miles from Earth” is difficult to read, as is the total in “The budget was 5,666,943,643 dollars.” In the first example, use the term of magnitude: “The binary star is more than 57 trillion miles from Earth.” Use the same approach for the monetary figure, which is unnecessarily precise; multidigit references to currency are often rounded off at two decimals past the degree of magnitude. “The budget was 5.66 billion dollars.”

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12 Responses to “5 Number Problems”

  • Mark Nichol


    Abbreviations of magnitude should be uppercased:


    I haven’t seen higher orders of magnitude abbreviated this way — “$10T,” for instance — but I’m not familiar with financial writing, so I can’t say for sure whether such usage exists.

  • Yvonne

    When abbreviating a large number in financial documents, say $46,000, is it correct to say $46k, or $46K? (lower case, or upper case?)

    And what are the other letter symbols used for higher numbers?
    k = thousand

    Is M used for million? As in $6M, or would it be spelled out 6 million?

  • Lena

    Tips 2 and 4 will be very useful for me. Thanks for the post Mark.

  • Mark Nichol


    Surely — except that, as I’ve explained in other posts, many websites use hyphens in place of en dashes.

  • Anna

    As a faithful reader from the UK, a note about currency symbols. Our currency is the pound, and confusion arises about the symbol for it, because Americans call this symbol ‘#’ a pound sign (we call it a “hash”). They symbol for our currency is this: £

  • Mark Nichol


    1. See this post for more information about styling numbers. Most books adhere to the number style recommended in The Chicago Manual of Style. I normally follow the one-to-one-hundred rule, rather than the one-to-ten rule, for whether to spell numbers out or use numerals, but I broke that style in this example for the sake of pointing out this problem for those who spell numbers out only to ten.

    2. David is right; I should have rounded the number up to 5.67.

    3. I’d spell out “third hole” in all contexts.

  • Janey


    Thanks for this list. Numbers are a pain, with rule inconsistencies further muddying the waters. I have three questions. The first two are from your list above. The last one is specific to a book I’m ghostwriting.

    1. From example one is a question that goes to rule inconsistencies. What are your thoughts on what number is used for the “spelling vs. numerical” cut off. I’ve heard 10 and 100. Since you used “28”, I’m assuming you use 10 as your cut off? Is there a particular reason?

    2. From example five, which David alluded to the rounding issue. Here you rounded down with a 6 as the next number. I’ve always heard that you round up if the next number is 5 or greater. What is the rule employed for rounding the number in this example and why?

    3. What about sports terms? Specifically I have scenes set on a golf course and refer to the hole they are playing. Should I type out “third hole” or “3rd hole”?

    Appreciate your detailed examples!

  • Sally

    Useful advice, Mark – thank you!

    [ I find “The Korean War lasted 1950-1953” rather odd anyway.]

  • Frank

    Regarding #2: as a total idiosyncrasy, for some time I have dropped the “.m.” from “a.m.” and “p.m.” in my e-mails. No one has complained; but then, I’m known for idiosyncrasies…
    Example: “Let’s meet at 12:30p for lunch!”

  • Shirley in Berkeley

    This is an invaluable list! I can never remember these distinctions and will surely return to it again and again. Thank you.

  • David Logan

    “The budget was 5.66 billion dollars.”

    “The budget was 5.67 billion dollars.”

  • Dan

    En dashes in number 2, surely.

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