Ask your friend to consider a number between 1 and 63 (his mind). Ask them to never tell you this number. Then show these 6 cards to your friend. "The number you think, on which cards?" ask your question. Let him show you these cards in turn.
Now it's your turn! You'il find the number he's thinking of in his mind.
For example, you get the first numbers 1,4,16 of the cards it shows.The number of persons selected from 1 to 63 is 21. Bingo ! (1+4+16=21)
For example, you get the first numbers 2,8,16,32 of the cards it shows.The number of persons selected from 1 to 63 is 58. Bingo ! (2+8+16+32=58)
This is a trick prepared according to the binary math system. For more details please check here.
Please, download pdf printable from the download link at the bottom of this page.
After printing on thick A4 paper (300-350 gr/m²), you can cut 6 cards and make them ready for use.