My magician gives you 3 regular dice
and asks you to do the following, while he is out of the room:
"Roll them, and write in sequence the three results, followed by a 3-digit number representing the hidden sides of the rolled dice.
Once you got the 6–digit number, divide it by 111.
THEN CALL ME."
Then he exits and you roll 1,2,4 and write down 124653, divide by 111 and get 1123.
The magician upon entering the room gets the result and quips within a second 1,2,4.
How did he do it?
If the digits of the 6-digit number are a,b,c,(7-a),(7-b),(7-c) in order then the result after division by 111 is 9(100a+10b+c)+7.
To perform the trick the magician subtracts 7 from the result and divides by 9 to determine the original rolls.
From the example, 1123-7=1116, 1116/9=124, and 1,2,4 are the original rolls, in order.
Posted by xdog
on 2017-12-12 09:44:36