Numbers cause a lot of difficulty for self-editors. They appear in a variety of jumbled forms within manuscripts as if the author is unclear of the rules. The confusion is most likely derived from the fact that technical writing and creative writing have different procedures. Today, we'll look at ten basic rules concerning numbers that will aid an author in the editing process.
1. Numbers that begin a sentence are always spelled out.
2. Numbers one through one hundred are spelled out. Also, hyphens are used for numerals such as twenty-two and eighty-nine, etc.
3. Whole numbers followed by hundred, thousand, or hundred thousand are also spelled out. Example: thirty thousand by 37,155.
4. When using whole numbers within millions, billions, or trillions, follow rule number two given above. Example: 220 million but three billion.
5. Percentages are usually written as numerals, with one exception: If the numeral begins the sentence, it is written out.
6. With regard to dates: the month is spelled out, the day and year are numerical. If a sentence begins with a year, the year is spelled out. For example: Twenty sixteen will be a very interesting year.
7. Centuries are spelled out and are not capitalized.
8. Decades can either be spelled out or expressed numerically. For example: the nineties or the 1990s (note if the decade is not clear, it is best to place it in numerals. As in this example, the nineties could refer to the 1890s). Note that when using numerals there is no apostrophe following the number unless the decade possesses something. For example: 1990s or 1990's tribulation.
9. Times of Day: There are a few rules to remember when writing time:
A. When using o'clock, the time is always spelled out.
B. Even, half, and quarter hours are also spelled out.
C. Exact times are written numerically. Please note that these exact times include the ante meridiem (a.m.) and post meridiem (p.m.) For example: 3:00 p.m. or 5:10 a.m. **Style note: check your publisher or targeted publisher's style guides. Some publishers such as Pelican Book Group prefer to use AM or PM, which is a variance from the Chicago Manual of Style (CMoS). If you do not include the AM or PM, however, the time is written out. For example: three forty (note the absence of the hyphen).
D. Numbers should never be used when referring to noon or midnight. For example: noon/midnight not 12:00 AM or 12:00 PM.
10. Interstate and Street Numbers: Interstate numbers are always written as numerals. Street numbers and addresses follow rule number two given above.
These rules are just a few to be utilized for numerals in fiction. The CMoS, currently in its 16th edition, is the source that most publishing houses follow. While expensive, the CMoS is a valuable tool for any author. It is also available and much easier to use online. Publishers sometimes differ with the CMoS, and that is a good reason to ask for the company's style guide.