Sorry for the abreviation in the title, the whole sentence wouldn't fit. Here is the original question:
Why is the difference between two numbers made by a different combination of the same digits, always equal to a multiple of 9? In other words: choose a number at random, then shuffle the digits in it to make a second number. Subtract the smaller number from the higher one. The result is ALWAYS a multiple of 9. (you can find this by adding all the digits in the number, and the sum will also be a multiple of 9). Why does this happen?
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I found this out due to this "mind reader":
http://www.digicc.com/fido/
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Thanks!
2006-06-17
05:08:05
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6 answers
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asked by
Anonymous
in
Mathematics