• Spell out and always use a numeral: 7 percent.
• Singular common nouns that end in s: add ’s. Ex. the class’s graduation party
• Singular proper nouns that end in s: add ’s. Ex. Davis’s book, Texas’s laws, Congress’s deadline
• Plural common nouns that end in s: add only an apostrophe. Ex. “the three dogs’ bowl”
• Proper nouns with plural form: add only an apostrophe. Ex. “United States’, General Motors’, the Petersons’ house”
• Follow Chicago 7.90.
president of Macalester
• In a first reference to President Rosenberg in external publications, give his title and full name: “President Brian C. Rosenberg.” Thereafter, refer to him as “President Rosenberg.” But, “Brian Rosenberg is the president of Macalester College” (lowercase “president”). (See also titles, personal.)
*To be sure that your proofreading changes are correctly understood, use the proofreaders’ marks found at merriam-webster.com/mw/table/proofrea.htm.