Apostropheses'

Kelly is right. As annoying as it is to see apostrophes used to show plurals instead of possessives, it is correct in some cases. The Associated Press Stylebook puts apostrophes on single letters (example: mind your p's and q's) to avoid confusion (mind your ps and qs?). And, as Kelly pointed out, "A" students don't get all As, they get all A's.

Merriam-Webster OKs apostrophes to show the plural of both letters and figures (her routine earned two 8's and two 9's).

American Heritage includes single letters and numbers and adds abbreviations.

People frequently use an apostrophe and s with their last names to show plural. You see it on mailboxes, welcome mats and such (Jones's, Smith's). They should add just an s for most names (Smiths, Andersons), and es for names that end in s, x or z (Joneses, Coxes). If they mean both plural and possessive, they should add an apostrophe after the final s (Joneses' House).

Many writers, this one included, frequently and accidentally use an apostrophe for plural when engrossed in writing. That's why it's important to proof your work.

Editor's trick: Edit for content from top to bottom; edit for spelling and punctuation from bottom to top.