May 21, 2010

Holy Number 7!

Math Geeking out



So I came across this really cool anomoly in simple arithmatic.

Pick any number that is a non-multiple of 7.

Now divide it by 7.

I don't know what the answer is to your specific number, but I can tell you one thing for certain. It's a number that repeats these six digits forever: "142857"

Crazy, right?

Go ahead give it a try:

1/7= _____
2/7= _____
3/7= _____
4/7= _____
5/7= _____
6/7= _____
8/7= _____
6,000/7= _____

WILD!

Also, I finally have a new video coming out next Wednesday, so keep an eye out for it.

5 comments:

  1. having become a pseudo math theorist i recognized the pattern you have up somewhat quickly. i don't know all of the intricacies but it is related to the 22/7 = pi phenomena. before modern advancements in mathematics 22/7 was the standard for pi, as a result the pattern you recognized in dividing non multiples by 7 is their relation to the curve of a perfect circle. like you said, a completely irrational number but a measurable occurance! fun with numbers!

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  2. In my experiments (mostly test 1) I have found that this is not always the case.

    (9/7)/9 is not equal to (6/7)/6 and some other cases (marked red). I find no pattern to when, or why, this occurs.

    But I don't do the same math as you do in your post.

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  3. The fact that you’re thinking about this for fun, somehow reminds me of the Barbie doll that says, “Math class is tough.”

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  4. That's interesting, but wait a minute...a repeating decimal is not an irrational number. If you dividing an integer by any other integer, in this case 7, by definition you get a rational number. You may get a repeating decimal if you choose to represent the answer as a decimal, but n/7 is a rational number for any rational number n. Irrational numbers by definition cannot be expressed as a ratio of two integers.

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  5. Thanks Bob for catching my slip up!

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