An assortment of metal number forms for a letterpress

Chicago Style Workout 77: Numerals

In Chicago’s default style for numbers, whole numbers under 101 are usually spelled out, as in three or ninety-three. Chicago’s alternative rule spells out numbers up to and including nine. But some expressions always call for numerals (July 2, page 9), and in scientific and technical contexts, numerals (also called digits) are the norm.

Top portion of title page for first edition of "Manual of Style: Being a Compilation of the Typographical Rules in Force at the University of Chicago Press; To Which Are Appended Specimens of Type in Use"

Chicago Style Then and Now

The first edition of The Chicago Manual of Style was published in 1906, when horses outnumbered cars and typewriters and telephones had only recently become fixtures of the modern office. Yet the books and articles published back then weren’t all that different from the ones published today, and a lot of the advice in the original Manual still applies.