I know in more formal writing, spelling out fractions is preferred (e.g. two-thirds), and in math no suffix is used, but I frequently see ordinal suffixes being used on fractions (e.g. 2/3rds), even from reputable news sources.

2/3 is already pronounced two-thirds and, to me, the addition of rds just looks weird and is certainly unnecessary.

Google turns up millions of examples:


Even legit news sources:


Wikipedia has nothing to say about it:


Is this proper English or just an undefined grey area?

  • I'd guess that it's used to make 2/3 read as a word, especially in headlines. Technically, it should be "2 3rds" – JeffSahol May 16 '12 at 3:00

The very first link from OP's Google search is Wikipedia's page on the "game" Guess 2/3 of the average. This doesn't actually include the characters 3rd at all, which is what I'd expect.

Google tries to interpret search terms in the most helpful way, but in this case it unavoidably implies greater prevalence for such use of the ordinal than actually occurs.

Searching Google Books for "up to 2/3 of" returns 34900 results, as against 771 for "up to 2 3rds of" (plus another 143 for "up to 2/3rd of", which looks really odd to me).

I'd be surprised if a recognised style guide recommended this use of ordinals - but even if there were any, it's obviously very much a minority position. For what it's worth, I think it looks slightly silly.

  • I realize that Google returns 2/3 as well as 2/3rds, but eight of the ten results on the first page are 2/3rds and all of the related searches at the bottom are 2/3rds. Second page is mostly 2/3rds as well. It certainly seems to be common. Books would more often use the two-thirds variety (over 400k for "up to two-thirds of"). – ThinkingStiff May 16 '12 at 0:21
  • @ThinkingStiff: The fact that the full written form also occurs a lot is irrelevant. In print, the headline numbers suggest 50:1 for avoiding the ordinal. For all I know, it might be more common on the net today than in print over history, but it's still a minority usage overall, everywhere. – FumbleFingers May 16 '12 at 2:46
  • I hate untypeset fractions; typewriters suck! We have computers now, not typewriters. That’s why proper fonts always have superiors and inferiors. Slick modern OpenType fonts can even have cool contextual rules that automatically apply them as needed. If your fraction isn’t one of the 19 premade “vulgar fractions” like ⅔ or ¾ that are currently defined in Unicode, then you set your fraction as ⁷⁷¹⁄₃₄₉₀₀ or whatnot. It looks so much better than this dumb 771/34900 crudola. – tchrist May 16 '12 at 3:18
  • @tchrist: How does one set fractions in comments? – supercat Oct 15 '12 at 18:49
  • 1
    @supercat Very carefully :) ¹³⁵⁷⁄₂₀₀₁ – tchrist Jul 29 '15 at 5:22

No, it is not. For example, use ¾ or three-fourths. Do not combine them, which is analogous to saying "ATM Machine" when what you mean is "ATM."

  • 1
    Or three-quarters, as most people would say. – Nicholas Shanks Jul 29 '13 at 18:28

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