Q. Hi. How do you write out grade levels? For example, would it be “third grade” or “3rd grade”? “Grade three” or “grade 3”? I cannot find the answer in CMOS 17; did I miss it? Thanks in advance!

A. Write “third grade” and “grade 3.” In Chicago style, the numbers zero through one hundred (CMOS 9.2) or, alternatively, zero through nine (9.3) are spelled out. This applies whether the number is a cardinal (“one”) or an ordinal (“first”). But numerals are preferred in many expressions where the number follows the noun. For example, we’d refer to page 3, act 7, room 9, and Highway 2. Examples like these appear throughout CMOS, but none with grade levels. We’ll try to add some in a future edition.