Magic Numbers

[Black Ned]

Number 9

9 x 2 = 18 --------------1 + 8 = 9
9 x 3 = 27 --------------2 + 7 = 9
9 x 4 = 36 --------------3 + 6 = 9
9 x 5 = 45 --------------4 + 5 = 9
9 x 6 = 54 --------------5 + 4 = 9
9 x 7 = 63 --------------6 + 3 = 9
9 x 8 = 72 --------------7 + 2 = 9
9 x 9 = 81 --------------8 + 1 = 9
9 x 10 = 90 -------------9 + 0 = 9
9 x 11 = 99 -------------9 + 9 = 18 --------------1 + 8 = 9
9 x 12 = 108 ------------1 + 0 + 8 = 9
9 x 13 = 117 ------------1 + 1 + 7 = 9
9 x 14 = 126 ------------1 + 2 + 6 = 9
9 x 15 = 135 ------------1 + 3 + 5 = 9

ETC ETC

Will this ever end?

Just a useless piece of information to bore the crap out of the whingers that don't see the funny and interesting things in life.

[ptc]

You have made my day.

[Terry B]

This uses the same principle as division by 3. If the sum of the digits in a number is divisible by 3 then so is the original number.
eg 93 /3= 31
9 +3 = 12 also divisible by 3

[silentC]

nerd alert!!

[AlexS]

...and if the sum of the odd digits in a number is the same as the sum of the even digits, the number is divisible by eleven.

...and if you multiply 12345679 by any multiple of 9 up to 81, the product is a 9 digit long string of the other factor. e.g 12345679 x 18 (9x2) = 222222222

How have you survived for so long without knowing this?

[silentC]

I repeat: nerd alert!!!

[AlexS]

I repeat: nerd alert!!!

Be alert: Australia needs lerts.

[Rossluck]

Number 9

9 x 2 = 18 --------------1 + 8 = 9
9 x 3 = 27 --------------2 + 7 = 9
9 x 4 = 36 --------------3 + 6 = 9
9 x 5 = 45 --------------4 + 5 = 9
9 x 6 = 54 --------------5 + 4 = 9
9 x 7 = 63 --------------6 + 3 = 9
9 x 8 = 72 --------------7 + 2 = 9
9 x 9 = 81 --------------8 + 1 = 9
9 x 10 = 90 -------------9 + 0 = 9
9 x 11 = 99 -------------9 + 9 = 18 --------------1 + 8 = 9
9 x 12 = 108 ------------1 + 0 + 8 = 9
9 x 13 = 117 ------------1 + 1 + 7 = 9
9 x 14 = 126 ------------1 + 2 + 6 = 9
9 x 15 = 135 ------------1 + 3 + 5 = 9

ETC ETC

Will this ever end?

Just a useless piece of information to bore the crap out of the whingers that don't see the funny and interesting things in life.


What a useless piece of information, it's boring the crap out of me. Can't you submit something funny or interesting? (if the hat fits....):wink:

[Grunt]

Be alert: Australia needs lerts.

I'm annoyed. Do we need Noyds too?

[bumnut]

....and did you know that the butter fat content of the south pacific sea cow is 47% higher than that of human milk....

[Tex B]

It's also true that 71% of statistics are made up on the spot.

Tex

[fred.n]

Save this for tomorrow boys:D

[fred.n]

We need Cliffs imput in this:p :D

[joe greiner]

Not quite as useless as y'all seem to think. This is the basis of a venerable old method of checking computations called "casting out nines." See for example http://en.wikipedia.org/wiki/Casting_out_nines

Joe