Saturday, May 20, 2006 - 05:28 AM

This is a quick trick you can pull off when playing dominoes with your friends by guessing the hidden domino, it's really simple!

1.- Ask your friend to take a domino tile (you must not see what it is)

2.- Ask him to pick a side of the tile, them ask him to multiply that number by 2

3.- Then ask him to add (any number you want, in fact it's better if he picks it)

4.- Ask him to multiply the result by 5

5.- Ask him to add the other side of the tile to the result

6.- Ask him for the result

7.- Substract (added number * 5) to the result

8.- You have now both numbers in the tile, however it's better to say it backwards to make it less obvious

Let's run through an example:

Let's say your friend picks 4-3

1.- Pick a number (4)
2.- Multiply by 2 (4*2=8)
3.-Add any number, ex: 6... (8+6= 14)
4.- Multiply by 5 (14*5= 70)
5.- Add the other side (70+3=73)
6.- Get the result (73)
7.- Substract (added # * 5) to result (73-(6*5)= 73-30= 43)
8.- You now have the answer (4-3), say it backwards just in case he tries to find a relation between the result he gave you and the actual result, so you say= 3-4

You can actually switch the 2 & 5 multipliers in steps 2 & 4, considering you have to consider the last multiplier in step 7, in fact better when doing the trick for a second time.

Obviously you could spare some time by just multplying the first number by 10 then add the other number (4*10=40+3=43); which is the same as just separating the 5 & 2 multipliers (5*2=10 remember?). The substraction of the added number is just to make it look more complicated than it actually is.

SRAD