I have these green cards which used to go to some magic trick but I no longer have the instructions. Does anyone know how the performance goes?
Ask a volunteer/victim to pick a number between 1 and 63. Then they tell you the letter of any papers on which they see their number. From that, you tell them their number almost immediately.
How it works
Each card shows numbers with a "1" in a certain digits place in binary. For example, any number with a "1" in the "ones" place [meaning the number is odd] is on card A. Any number with a "1" in the "thirty-twos" place [meaning >+32] is on card F.
So you just make a number from that. To do it quickly, add up the numbers of each place based on letters: A=1, B=2, C=4, D=8, E=16, F=32
Just add up the values of the letters they say, and that's their number!