Chaotic42's fact of the day: 6/21

[Chaotic42]

Most of you know that if you keep adding up all of the digits of a multiple of 9, you'll always get 9.

For example 9*652241=5870169

5+8+7+0+1+6+9=36
3+6=9

This isn't just a decimal thing. It's a characteristic of any number n where the number system is base n+1. So in octal, 7 has this characteristic. In hexidecimal, it's f. In binary, it's 1. In a base-343828 number system, it's 343827.

[EXEcution]

umm who else understands this?

[Death Engineer]

I do. Intro to Number Theory. I took it as an elective. Was very interesting. Was the only Math class I took in college that I didn't get an 'A' in (I got a 'B'). It was voted the hardest class in the Math Major curriculum by the Math Major students at the University of Texas. :cool:

Correction: I just realized that it was Algebraic Structures I and not Intro to Number Theory. :wacko:

[JIMINATOR]

sorry, i lost my book below, but it does make sense.

[Scorch]

I learned about it in math class this year. :thumbs:

I hate it. :thumbs:

[solid snake295]

cool, i get it

[Chaotic42]

Yeah, I was thinking about this on my way home from work and I realized it worked for octal, binary, and hex. It's a property of one less than the number system.