How does this work?

[DUD]

We have done this about 25 times and the answer is always right, I don't know how it does it. Do You? Bill



http://trunks.secondfoundation.org/files/psychic.swf

[ryan.s]

The number you come up with after doing the adding and subtracting will always be a mutiple of 3. If you look at the chart of numbers all numbers that are a mutiple of 3 starting with 6 have the same symbol.

[just4funsies]

It's just a number trick. Out of that whole chart, the only numbers that matter are 81, 72, 63, 54, 45, 36, 27, 18, 9, and 0. This is because, no matter what your "pick" number is, your "result" number will ALWAYS be one of these (all picks in 90's end up at 81, all picks in 80's end up at 72, all picks in 70's end up at 63, and so on). If you look at the chart, all the symbols for those ten "result" numbers are exactly the same. The "magic" symbol always matches whatever symbol the program assigns to those ten numbers. The key symbol changes each time, to make things look more random, but it is always the same across those ten key numbers, and the "magic" symbol always matches that symbol.

[RayintheUK]

All answers are multiples of 9. Start with the lowest two-digit number (10), add the digits together and subtract them from the original number and the answer's always 9 until you get to 20, when it's 18. 30s are 27, 40s are 36, 50s are 45, 60s are 54, 70s are 63, 80s are 72 and 90s are 81.

Therefore, no matter what range of numbers you choose, the answer's always a 9 multiple. Look now at the symbols alongside the numbers (which change every new try). All the multiples of 9 have identical symbols.

All that needs to be done is to randomise the appearance of each of the identical 9-multiple symbols, mixed in with all the other numbers, the vast majority of which can never crop up as answers to the sum - job done!

Ray.

[scorrpio]

Any 2-digit number XY is X*10 + Y. Sum of its digits is X+Y, so the result is always (X*10 + Y) - (X + Y) = X*9 - the 1st digit of your original number multiplied by 9.

[Ken Massingale]

Any 2-digit number XY is X*10 + Y. Sum of its digits is X+Y, so the result is always (X*10 + Y) - (X + Y) = X*9 - the 1st digit of your original number multiplied by 9.

Now I have a headache!