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Q. Hi—My Manual of Style is buried in a box at home after a move, and we’re having a debate at work. When should numbers be spelled out, and when should they be written in numerals?
A. Chicago’s general rule is expressed in CMOS 9.2: “In nontechnical contexts, Chicago advises spelling out whole numbers from zero through one hundred and certain round multiples of those numbers.” Since there are numerous exceptions and special cases, however, you really need to finish unpacking and read chapter 9. (I can’t believe you forgot to put CMOS in the “Open Me First” box with the toilet paper, box cutter, and Band-Aids.)