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.

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? 

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?

Q. Should hundred be repeated in spelled-out number ranges such as “one to three hundred” (meaning 100 to 300)?

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?

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.”

Q. Our organization just had a raging dispute about the use of the term “the 1910s.” This term is actually going to be used in a photo caption in a book. I’m astounded! What do you think of this?

Q. Are digits (e.g., 4, 8) appropriate for use in illustrations or diagrams to save space, even if they would be spelled out in text (e.g., four, eight)?

Q. In the following conversion in prose, should it be written “six feet (1.80 meters)” or “six feet (1.8 meters)”?

Q. Is there a correct way to write a range of only two numbers in a complete sentence? For example, June 3–4, or June 3 and 4? Pages 75–76, or pages 75 and 76? The issue gets especially ugly when referring to multiple numbers. For example, “The event will take place Nov. 3 and 4, 8 and 9, 15 and 16, and 21 and 22.” Yuck. I say that for ease of reading, an en dash would be used. However, I know that according to CMOS, an en dash between two numbers implies “up to and including,” or “through.” With that in mind, should “and” be used, because no number comes between the two numbers that are cited? Or is that overthinking things?