Numbers

A. According to Google’s Ngram Viewer, numerals have been consistently more common in that expression in published books—but only slightly.

Would “1 to 10” be even more popular if CMOS 9.2 didn’t advise spelling out numbers one through one hundred in most contexts? Maybe.

But you can take this answer as permission to use numerals, which seem to do a better job than spelled-out numbers at suggesting the hypothetical scale in that expression.

A. Where CMOS fails to offer a specific ruling, follow common usage. This often means looking to Merriam-Webster, but since there’s no entry there, you’ll have to do some digging.

Pencil companies seem to prefer the form “No. 2” (as on this page from Dixon Ticonderoga), though “#2” is also common. According to Google’s Ngram Viewer, those forms also happen to be at or near the top of the list of how such pencils have been referred to in books published since 1900. Book editors often default to spelling out abbreviations and numerals in running text, but even so, most of the spelled-out forms trail the abbreviations:

And though “number 2 pencil” would be okay with us—in line with “type 2 diabetes,” “size 10 dress,” and “type A executive” (see CMOS 7.89, sec. 2, under “noun + numeral or enumerator”)—we’d argue from the evidence above that “No. 2” will be more familiar to readers.

A third option—spelling out the whole thing (“number two”)—would be okay also (it’s the second most common usage). But as with dress sizes (and page numbers), a numeral matches what’s usually on the item itself.

As for the capital N in “No.,” there’s a close analogy in “No. 1”—as in “we’re No. 1.” That’s how “number one” in that sense is “often written” according to Merriam-Webster. It’s maybe not surprising, then, that the form “no. 2 pencil” (lowercase n) doesn’t even chart in an ngram (unless its absence stems from a limitation in Google’s data).

As most editors who work on paper would know, the “2” refers to hardness. A No. 2 pencil leaves less graphite on the paper than the softer No. 1 (which makes darker marks), but more than the harder No. 3 (which makes lighter marks). According to a more common classification system, a No. 2 pencil is an HB. H refers to hardness, B to blackness. So whereas an H pencil would be hard (and light), a B would be soft (and dark); HB is in the middle. These grades can also include numbers. For example, an 8B is softer than a 6B.

For more information on these and other details, see The Pencil: A History of Design and Circumstance, by Henry Petroski (Knopf, 1990).

A. There are at least two principles at work in these two questions.

First, though numbers are often spelled out in dialogue (to help readers understand how they would be spoken), that doesn’t mean numerals are never used. Fictional room 305 would almost never be encountered in the real world as “room three oh five” or “room three hundred five” (or “three hundred and five”), least of all on an actual hotel room door. So “room 305” is the best option, even in dialogue; it’s how room numbers are known.

The second principle is precision. Passing mentions of temperatures, whether in dialogue or narration, would be spelled out in Chicago style: “Brrr, it must be ten degrees below zero out here!” (or “Brrr, it must be ten below out here!”). But freezing points and geometric angles represent exact measurements, and numerals are often the best way of communicating these in ordinary prose.

In dialogue, however, spelling out exact quantities suggests a different kind of precision—another meaning of spell out is to make something clear—so words would work at least as well as numerals:

“Freezing point is zero degrees Celsius,” he announced.

“I can draw a perfect forty-five-degree angle,” she bragged.

You might make an exception, however, if the character is referring to an actual numeral somewhere:

“The thermometer says 32 degrees,” I said, squinting at the display.

That “32” might help the reader imagine the scene, making the dialogue seem more realistic (much as writing “305” in the previous example would).

So numerals can work in dialogue for expressions that would always be written with numerals or when a character is referring to actual numerals; otherwise, it’s usually best to spell them out. In narrative, Chicago’s general rules for numbers apply—subject to editorial discretion. For more on this topic, see “Numbers in Creative Writing” at CMOS Shop Talk.

A. You’re right. Numerals are shorter than words, and they are arguably easier to read. Plus, an all-numeral style would make an editor’s job easier. But the digits in a number like 7 imply a precision that’s usually reserved for the sciences and other technical contexts. Even in the sciences, numbers in the form of ordinals are often spelled out below 10th, on the principle that an ordinal refers to a ranking rather than to a precise quantity.

On the other hand, numerals are customary in certain contexts even in the most literary of prose. In Chicago and most other styles, for example, you’d use digits to refer to page 3 or page 115, a bulb of 40 watts (or 450 lumens), and a 3 percent raise issued on February 1. But aside from these and (pun alert) a number of similar exceptions, words are still Chicago style below 101 in nontechnical settings and below 10 in journalism and technical (but not purely scientific) contexts (see CMOS 9.2 and 9.3).

You can blame the persistence of spelled-out smaller numbers outside the sciences on a combination of tradition and reader expectations, two (not 2) factors that tend to reinforce each other.

A. AP style makes sense for reporters, who often need to achieve clarity in the fewest possible words. And for those of us who haven’t memorized the chronological sequence of NFL championship games, “1969 Super Bowl” is more meaningful than “Super Bowl III.” However, both are correct, and you can use the latter when you’re not following AP style. As for the number, you could always refer to “the third Super Bowl,” but to reflect how the game is generally known, you wouldn’t write “Super Bowl 3”—in spite of what AP might say—any more than you would describe Joe Namath (the winning quarterback in that contest) as having worn number XII (or even number twelve) on his jersey. In other words, it’s Super Bowl III (and number 12).

A. Chicago’s alternative rule for spelling out numbers, like the general rule, applies equally to cardinals and ordinals. If you’re following the general rule (and spelling out zero through one hundred), you would refer to the seventh and seventeenth centuries; for the alternative rule (zero through nine), you would refer to the seventh and 17th centuries. That approach works for occasional references to either or both centuries. But if you need to refer often to both one- and two-digit ordinals in the same context, you can use digits for all of them for the sake of local consistency (e.g., “the 7th and 17th centuries”). See also CMOS 9.7.

A. CMOS normally spells out numbers up to one hundred, cardinals and ordinals alike (i.e., “five” and “fifth”; “eighteen” and “eighteenth”). But we recognize that in some contexts numerals are preferred (e.g., “page 5” and “5th ed.”). If that’s the case in golf, you have our permission to comply. But consider also the advantages of referring to, for example, a “par 4 fifth hole,” where a mix of numerals and words might be helpful. And note that the fabled nineteenth hole is often so spelled. Whatever you decide, let consistency and clarity be your guide.

A. That example in chapter 8 is intended only to illustrate that when a decade or century is written in words, such an expression isn’t capitalized. Our usual preference would be for numerals (“1800s”), but either form is acceptable (choose one and be consistent). Note that Chicago considers “1800s” to be equivalent to “nineteenth century”—which also happens to be the more common way of expressing a century in words. (Under Chicago’s alternative rule for numbers, according to which numerals are used for numbers greater than nine, it would be “19th century”; see CMOS 9.3.) We should also note that in Chicago style, “1800s” and “1900s” refer to the whole century, not just the first decade. For more, see our post on decades at CMOS Shop Talk.

A. Consistency isn’t always a realistic goal with numbers. For example, no one would write a sentence like this one: “We counted 5.3 million fish in the year 2 thousand, but somehow I managed to catch only 3.4 tens.” In your example, “470 thousand” would be almost as intelligible as “470,000,” but the usual convention is to reserve a mix of words and numerals for millions and above—a cutoff designed to prevent strings of digits that are longer than their verbal counterparts would be (see CMOS 9.8).

A. We get this question a lot. Let’s start with the conventional formats—July 24, 2020 (typical US style); 24 July 2020 (typical style outside the US); 2020-07-24 (ISO style). Each of these uses a cardinal rather than an ordinal numeral for the day, whether the year is expressed or not (i.e., July 24 or 24 July, not July 24th or 24th July). Outside of these conventional formats, our recommendation would be to spell out ordinals for the day of the week even when the month is mentioned: the twenty-fourth of July; the twenty-fourth (but the Fourth of July or the Fourth for the US holiday; see CMOS 8.89). But keep in mind that this rule applies primarily to formal, long-form prose—so it’s possibly a little too formal for many contexts; if you prefer numerals, or if you need to use them to save space, you have our blessing (the 24th of July, or the 24th). And if you follow Chicago’s alternative system of spelling out only one through nine, an all-numeral approach for days will facilitate consistency (e.g., we’ll be offering tours on the 1st, 2nd, and 24th of July).