I am unsure where to put this, but here goes... I suppose you all know that guessing game - Cows and Bulls or Mastermind or anything with the same general idea. :) Requireing nothing more thant a pen and paper, I remember we used to play it when we got bored in classes, worked just fine in passing the time. After a while we got to a point where we solved each others numbers in 5-7 moves and it seemed increasingly that at this point luck and whoever started first had more to do with winning than thinking. So we began wondering about the mechanics of the game. Like whats the minimum number of moves you need to guess the number. What moves should be must. How would it work with diffrent numerical systems/diffrent number of symbols/digits to guess. What is the optimal ratio of digits-positions and repeating digits are a bit confusing as well. Maybe some of you can even figure out a math algorithm for an optimal solution.