Forming the Plurals of Numbers, Letters, and Abbreviations
Rule: The plurals for capital letters and numbers used as nouns are not formed with apostrophes.
Example: She consulted with three M.D.s. BUT
Example: She went to three M.D.s’ offices.
The apostrophe is needed here to show plural possessive.
Example: She learned her ABCs.
Example: the 1990s, not the 1990′s
Example: the ’90s or the mid-’70s, not the ’90′s or the mid-’70′s
Example: She learned her times tables for 6s and 7s.
Exception: Use apostrophes with capital letters and numbers when the meaning would be unclear otherwise.
Example: Please dot your I’s.
You don’t mean Is.
Example: Ted couldn’t distinguish between her 6′s and 0′s.
You don’t mean Os.
Posted on Thursday, March 27th, 2008, at 8:31 pm