I have written a number on a piece of paper. Now you have to answer some questions so that I can predict the the number that you pick: What is 5 times 5? What is 6 times 6? What is your favourite colour? Pick a number between 1 and 10. What number did you pick?
take someone aside and quickly bombard them with maths questions to which the answer will always be 6 (what is 2x3, what is half of 12, what number is half a dozen - etc) and then get them to immediately name a vegetable
they should respond "carrot" at which point you will produce a piece of paper upon which you wrote 'carrot' beforehand
Not much bbb. All previous questions are there just to make it less likely you'll think about the final answer much and just instinctively pick one (about 3/4s of the way up the permitted range).