Q. Regarding spelling out round numbers over one hundred—how should we handle numbers like 1,500? It’s more round than a number like 1,543, but it’s also less round than a number like one thousand. And if it should be spelled out, which is preferred, “one thousand five hundred” or “fifteen hundred”? Thanks!
A. According to CMOS 9.4,“The whole numbers one through one hundred followed by hundred, thousand, or hundred thousand are usually spelled out.” The spelled-out form “fifteen hundred” qualifies. But the hybrid form “one thousand five hundred” does not. Paragraph 9.4 is intended to encourage spelling out round numbers like three hundred thousand, not awkward forms like “three hundred thousand six hundred”—or, for that matter, something like “thirty-three hundred thousand,” which would be better expressed as “3.3 million” (see CMOS 9.8). So write “fifteen hundred” or “1,500,” depending on context. (For example, if numerals are otherwise rare in your text, opt for the former.)
Q. In the context of computer bits, would you make an exception to the rule about spelling out numbers under 10 (Chicago’s alternative rule), or would you still spell out “zero” and “one”? For example, “Information is represented in bits as 0s and 1s.” Is that correct?
A. When expressing binary bit strings (or any specific numeric component thereof), it makes sense to use numerals: e.g., 11111100011 (binary for 2019). But when discussing binary numbers as a concept—as in your example—you can refer to zeros and ones as the basis of the system. This has the advantage, among others, of avoiding the plural forms 1s and 0s (which in some fonts will look almost like words).
Q. What is the CMOS stance regarding the use of numerals for a year at the beginning of the sentence? For example, “1980 was indeed a good year.” I see that AP allows it, but I don’t know if you do.
A. CMOS still recommends spelling out any number at the beginning of a sentence (see CMOS 9.5). If the result is awkward, as it often is with a year, the recommendation is to reword: The year 1980 was indeed a good one. This rule is an editorial nicety: a numeral isn’t as effective as a capital letter at signaling the start of a new sentence. In other words, it’s a rule you can break in all but the most polished, CMOS-approved prose—for example, you can ignore it in casual correspondence or where space is at a premium (or if you follow AP style!).
Q. I am preparing an online archive. Many of the items are audio or video recordings. I’ve fruitlessly searched CMOS for the proper way to indicate the total time of a recording—for example, thirty-five minutes and thirty-three seconds. 35 min. 33 sec.? 35m:33s?
A. There are various accepted stylings. At CMOS 14.264 (“Recorded Readings, Lectures, Audiobooks, and the Like”) one example shows the length of a reel-to-reel tape as 1:12:49, and another shows the length of an audiobook as 13 hr., 6 min. An example at CMOS 9.40 (“ISO Style for Time of Day”) suggests the option of putting a zero in front of a single-digit measure of time: 09:27:08.6 = 27 minutes, 8.6 seconds after 9:00 a.m. Based on all these examples, you could use either 00:35:33 (to clarify that it’s 35 minutes, not 35 hours) or 35 min., 33 sec.
Q. Which of the following is correct or preferred? I’m guessing it’s the first option. I’m working on a very important, time-sensitive document, and everything has to be correct according to CMOS.
She’s number one in my book.
She’s number 1 in my book.
She’s No. 1 in my book.
She’s no. 1 in my book.
A. All of those stylings are widely accepted. The default Chicago style for numbers one through ten is to spell them out, so “number one” works well. In certain contexts (such as referring to a list), you might opt for “number 1,” based on Chicago style for “page 1”, “table 1,” and other such expressions.
Q. Why, in many book titles that include ranges of years, is Chicago style for inclusive numbers not followed? As I understand it, Chicago style is to elide the first two digits of the four-digit second number if they are the same as the first two in the first number of the range. The publisher I work for, like many others, follows that rule in general text. But consider, for instance, the subtitle “Self-Portrait of an Actress, 1920–1956.” Do most readers prefer to see titles with ranges of years styled like this one?
A. You’re correct about Chicago’s style for inclusive dates when a writer chooses to abbreviate them, but CMOS is also fine with spelling them out. In fact, paragraph 9.64 says, “In book titles it is customary but not obligatory to repeat all digits.”
Q. Can you inform me how you would recommend writing out “10:05 a.m.” if an author is very set on using words rather than numerals?
A. Certainly. You can write “five past ten in the morning,” for instance. There are various ways to write times of day. Please see CMOS 9.37 (“Numerals versus Words for Time of Day”) for more suggestions. Please note that it’s conventional to use numerals for odd times like 10:05, however. Spelling out is usually reserved for the hour, half hour, and quarter hour.
Q. Should hundred be repeated in spelled-out number ranges such as “one to three hundred” (meaning 100 to 300)?
A. Because “one to three hundred” can be mistaken for “1 to 300,” it’s important to spell out “one hundred” anytime there could be the least doubt.
Q. Phone numbers. The US convention is sort of (Area Code) PRE-Number. International is all over the place. Any advice on presenting these in a consistent manner? In particular, I want to set a style rule for my company, which is US-based but has mostly international customers, so I want to include the country code as well. I’m leaning toward spaces separating the elements: +1 222 333 4567. Any thoughts?
A. CMOS 17 has a new section covering telephone numbers (9.57) that agrees with you on the use of spaces instead of hyphens for international numbers.
Q. In the money examples in the hyphenation guide, I would not have allowed the last example, “a $50–$60 million loss.” Almost certainly “a $50 million to $60 million loss” was meant, but the construction reads “fifty dollars to sixty million dollars.”
A. Luckily, in most contexts misreading is unlikely in the way you suggest (“Yes, it was a bad year; I suffered a loss between fifty dollars and sixty million dollars”). In the rare instance where such an expression could cause confusion, a writer should expand the range.