Q. My coworkers and I are debating what exactly is meant by the word isolated in CMOS 9.20 (“isolated references to amounts of money are spelled out for whole numbers of one hundred or less”). One opinion is that two or more references to amounts of money in one sentence no longer qualify as isolated, as in “He had $0.21 and she had $21.00.” The other opinion is that one sentence containing two or more references to amounts of money could still qualify as isolated if the surrounding text does not mention money, as in “He had twenty-one cents and she had twenty-one dollars” in a passage contrasting the two people personally with no other reference to money. Could you please settle our debate?
A. By isolated references, we mean references not grouped in a table, list, financial report, equation, tax form, or budget. We mean numbers that come up in a generally nonnumeric context, such as a novel or a history textbook or a blog post about the election—even if there are more than two amounts of money in such a context. Even if there are more than three. Heck—even if there are more than four.
The idea is to spell out amounts of money unless they become hard to read or compare, or too many to keep track of. Because the choice between numerals and words requires judgment, it would be counterproductive to make a rule about it. The CMOS standard you seek is not a magic number of references but simply the writer’s common sense.