Mathematical mind reading magic trick

Follow these instructions to amaze your friends with your mind reading abilities using simple maths and a couple of tricks. A fun game to play with your friends

You will need

  • yourself
  • a friend.

What to do

Try this mind reading game on a friend.

Ask him or her to follow these instructions (cautioning them to keep their answers in their head):

  1. Pick a number between 5 and 9.
  2. Subtract 5.
  3. Multiply by 3.
  4. Square the number (multiply by the same number).
  5. Add the digits until you get a single digit (for example, if your number was 64 then add 6 + 4 = 10; then add 1 + 0 = 1).
  6. If the number is less than 5, add 5; otherwise subtract 4.
  7. Multiply by 2.
  8. Subtract 6.
  9. Relate the number you now have with a letter in the alphabet where 1 = A, 2 = B, 3 = C and so on.
  10. Pick the name of a country that begins with that letter.
  11. Use the second letter of the country and think of an animal that begins with that letter.
  12. Think of the colour of the animal.

When your friend has done all this, tell him or her that they're thinking about a grey elephant from Denmark. Watch their surprise as they realise you've successfully predicted the outcome!

What's happening

Steps one to eight will always give you the number 4 (test it and see), so step nine will give you the letter 'D'. Most people think of 'Denmark' in step ten (because, besides Denmark, there aren't many well known countries starting with 'D') and then will think of 'elephant' for an animal starting with 'E'. Finally, all elephants are grey.

It's amazing how often this trick works, though it won't work all the time. When we did extensive field testing on this trick we found a few people came up with brown echidnas and emus!

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