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The Apostrophe with Numbers, Letters, and Abbreviations

Rule 1: The plurals for capital letters and numbers above nine do not require apostrophes, but some use them anyway.

Examples:
She learned her ABCs.
(some writers prefer ABC’s)
the 1990s (some writers prefer 1990′s)

Rule 2: For clarity, most writers use apostrophes with single capital letters and single-digit numbers.

Examples:
Please dot your I’s.
She learned her times tables for 6′s and 7′s.

Posted on Monday, November 9, 2009, at 10:28 am


2 Comments

2 Responses to “The Apostrophe with Numbers, Letters, and Abbreviations”

  1. Angela says:

    How about apostrophes to show possessive after abbreviations ending in S? Danish company names mostly end in A/S or ApS (initialisms), so would the correct form be e.g. Trading Company A/S’s sales in 2013… or would you just use an apostrophe without the s?

    • Jane says:

      In this case, we recommend adding ‘s after the name for clarity: A/S’s sales, ApS’s marketing strategy. However, some authorities recommend just an apostrophe after proper nouns, including company names, when they end in the letter s.

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