Well, the number's always going to be a multiple of 9 and all the 9 multiples have the same symbol. You get the illusion because which symbol is used on the 9s changes each time it's done.
For the maths
Think of it as picking 2 numbers, x & y.
If x = 5 and y = 3, your number is 53 : 10x + y
Now subtract (x+y) and you get
10x + y -x -y = 9x which will always be a multiple of 9.
For the maths
Think of it as picking 2 numbers, x & y.
If x = 5 and y = 3, your number is 53 : 10x + y
Now subtract (x+y) and you get
10x + y -x -y = 9x which will always be a multiple of 9.
Paul C. Anagnostopoulos
Nap, interrupted.
- Joined
- Aug 3, 2001
- Messages
- 19,141
Oh my God! It's even more amazing than that! You can add the two digits of your chosen number, then reduce that again if it's still two digits, then subtract the result from your original number and it still works!
Double oh my God! You can even add up the two digits of the difference and pick that number!
It couldn't have anything to do with math, because I'm no good at math.
~~ Paul
Double oh my God! You can even add up the two digits of the difference and pick that number!
It couldn't have anything to do with math, because I'm no good at math.
~~ Paul
DangerousBeliefs
Graduate Poster
- Joined
- Aug 25, 2003
- Messages
- 1,299
Hey NWilner.
Here's a simple answer... keep using the same number over and over... notice that the symbol keeps changing and that symbol is the same one in the magic ball?
That's your answer. Some of the numbers (the "magic" ones) all have the same symbol as the magic ball... every time.
Here's a simple answer... keep using the same number over and over... notice that the symbol keeps changing and that symbol is the same one in the magic ball?
That's your answer. Some of the numbers (the "magic" ones) all have the same symbol as the magic ball... every time.
There's another trick which works along similar lines.
You're presented with 4 cards and asked to concentrate on one. The magic application will sense which one you are concentrating on and remove it from the set. You click the button and - lo - your card is gone.
Took me a few goes to figure out that all the cards change with each click - but to similar values (i.e. you don't get cards changing suit, or from picture to non-picture) and because you're concentrating on one card, you don't spot the others. Works surprisingly well.
You're presented with 4 cards and asked to concentrate on one. The magic application will sense which one you are concentrating on and remove it from the set. You click the button and - lo - your card is gone.
Took me a few goes to figure out that all the cards change with each click - but to similar values (i.e. you don't get cards changing suit, or from picture to non-picture) and because you're concentrating on one card, you don't spot the others. Works surprisingly well.