Fred Lunnon <fred.lunnon@gmail.com> wrote:

As a rather nerdy schoolboy, I read somewhere an apocryphal quote by an Alaskan old-timer that "in Winter, the temperature stays forty below". For many years I wondered now and again whether this was in degrees Centigrade or Fahrenheit.

He may have meant only one or the other, whether or not he knew that they were the same. Which reminds me of the question about how many numeric dates are ambiguous, given that they can be written with the month either first or second. For instance 7/4 can mean July 4th or the 7th of April, but there's no ambiguity about 11/13, since there's no 13th month. You can argue for either 144 or 132, depending on whether you consider a date such as 9/9 as ambiguous. Does it mean September 9th or the 9th of September? They're the same date, but it remains ambiguous which 9 in 9/9 refers to the month.