31th or 31st?

Incorrect spelling, explanation: ordinal numbers have two ways of writing them down: full-word form and number form. The latter is written as a number with the abbreviation of the word form with it; for example, fourth → 4th. This rule applies to all ordinal numbers, so thirty-first will be written as 31st, not 31th.

Correct spelling, explanation: the short form of this number should be written as 31st because in its full-written form it is thirty-first. At the end of the word, there are letters st which are added as an abbreviation at the end of the number form of ordinal numbers. We can’t use the form 31th because this number isn’t pronounced with th at the end.

Definition of 31st:numeral, the ordinal number between 30th and 32ndCan you believe it was his 31st time in jail?

Incorrect spelling

Incorrect spelling