Apostrophe rule: 100s or 100’s?

[This entry originally appeared on Clare Lynch’s blog, goodcopybadcopy]

This addendum to my previous blog entry on apostrophes is dedicated to the graphic designer friend of mine who recently posted a cry for help on Facebook, asking which was correct: 100’s or 100s.

Naturally, her writer friends told her to ditch the apostrophe, which she did. Sorry to distress any literate people out there, but I have to inform you that she has since revealed that she was told to put them all back in.

So let me restate my rule number one for apostrophes: never, ever add ’s to the end of a word just to make it plural.

This rule applies for figures. So 100s and 1,000s are both correct. Please note that 100’s is wrong and will make any sensitive reader’s eyes bleed.

And while we’re here, may I just say that the same rules I outlined in my last post also apply to abbreviations. The following are all correct:

100s of British MPs have fiddled their expenses, it’s claimed (plural, not possessive)

The MP’s wife was also implicated in the expenses scandal (singular, possessive)

MPs’ expenses will have to be closely looked at in future (plural, possessive)

Would the BBC – or any other publication that I’ve spotted getting it wrong – please take note.