Trick: the spectator rolls a pair of invisible dice. After doing what seems like some random math, the magician
divines the numbers that you rolled.
The magician hands someone an invisible pair of dice. He asks them to roll the dice and inquires, What number did you roll?
After their response, the magician insists, "Roll them again." Upon compliance, the magician asks, "What number did
you get this time?" After the person responds with a different number, the magician proclaims, "So they are not loaded!"
Everyone chuckles.
The magician asks that they roll the dice one last time. He adds, "This time don't tell me what you rolled. Instead
choose one of the two numbers that you rolled and double it. Now add five to your new number. Multiply the result by
five and add the number on the other die to it. What is your new total?"
Upon their response, the magician astonishes everyone by revealing the numbers that they rolled. The magician adds, "Do you
know how I guessed your numbers? It was easy ... you left the dice sitting on the table."
SECRET: The real method uses a little math.
Let's say they rolled a 5 and a 2.
If they choose the five, and double it, that makes 10.
Adding 5 to 10 makes 15.
Multiplying 15 by 5 equals 75.
Adding the other number 2 to that total equals 77.
The secret is to subtract 25 from this last total to get 52.
The result 52 translates that they rolled a 5 and a 2.
This always works.
Now here is the algebra to prove it.
Let x = 1st number and let y = 2nd number.
Choosing the 1st number and doubling it yields 2x.
Adding 5 to it gives us 2x + 5.
Multiplying by 5, you get 10x + 25.
Then adding the other number y, you get 10x + 25 + y.
When you subtract 25, you get 10x + y.
10x just moves the number x to the tens column so that y is in the units column.
Please visit Diamond Jim Tyler's website at
www.djtyler.com.