Writing ordinal numbers: 31st or 31th / 72nd / 178th

Discussion in 'English Only' started by white_ray, Oct 23, 2008.

  1. white_ray

    white_ray Senior Member

    Portuguese PT
    Hello all,
    A colleague of mine has a doubt about the usage of ordinal numbers in English.
    Which one is correct: 31st or 31th? 41st or 41th (of October) and so forth?
    I always used 31st/41st etc. but after some research I noticed that 31th/41th etc. appear a lot.
    Any insights into the usage of these ordinals are welcome. :)
  2. Vodoun Member

    English - America
    Anytime it ends in a 1 it will be 1st (21st, 141st)
    ends in a 2 it will be 2nd
    ends in a 3 it will be 3rd
    ends in 4, 5, 6, 7, 8, 9, 0, it will be 4th
  3. polly2009 New Member

    i want to know how is the right way of writing the numbers on this sentences:

    this value decreased exponentially during the sedimentation until the 72nd hour.
    At this point the total contamination became constant to about 800 mg/kg until the 168 th

    thanx a lot!!
  4. ace02nc Senior Member

    English - United States
    What you have here is correct, but typically in technical/scientific documents such as these, you will see it written as Hour 72, Hour #168, etc.

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