March 2017 Fiendish Function

The Fiendish Function posed during March 2017 had the following sample guesses and replies:

  • GUESS
  • REPLY
  • 1
  • 5
  • 2
  • 5
  • 3
  • 4
  • 4
  • 4
  • 5
  • 4
  • 10
  • 5

The rule was: "Count the number of letters in the word for the number, then count the number of letters in the word for that number".

Suppose the guess was 17:

  • Count the number of letters in "seventeen", giving 9.
  • Count the number of letters in "nine", giving 4.

So the result is 4.