# Math: .99repeating = 1?

**URL:** <https://boards.straightdope.com/t/math-99repeating-1/11021>\
**Category:** Factual Questions\
**Created:** [April 12, 2000, 1:59pm UTC](https://boards.straightdope.com/t/math-99repeating-1/11021 "2000-04-12T13:59:00Z")\
**Posts on this page:** 4\
**Page:** 5

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**Author:** ![Kamino\_Neko](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kamino_neko/32/34_2.png) [@Kamino\_Neko](https://boards.straightdope.com/u/Kamino_Neko)\
**Post date:** [April 25, 2000, 12:00am UTC](https://boards.straightdope.com/t/math-99repeating-1/11021/81 "2000-04-25T00:00:00Z")

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> [@](#):
>
> Originally posted by Jinx:  
> **But, technically speaking, we realize such numbers continue ad infinitum. Well, at least I think we’d agree that 0.999… does!**

And here you’ve hit on positive proof that 0.999… _does_ equal 1!!!

0.999… is a decimal point followed by (n) 9s.

The difference between 1 and 0.999… is thus a decimal point followed by (n-1) 0s, and a 1.

However, since (n) equals infinity, (n-1) _also_ equals infinity.

THEREFOR, there is nowhere for the one to go.

0.000(…)1 == 0!

Therefor, the difference between 1 and 0.999… is **0**.

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_Eschew Obfuscation_

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**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\
**Post date:** [April 25, 2000, 9:53am UTC](https://boards.straightdope.com/t/math-99repeating-1/11021/82 "2000-04-25T09:53:00Z")

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> [@](#):
>
> Originally posted by Jinx:  
> **The practical boys got to kiss the girl. The theorists are still trying to complete the task today. …And that is the rub, ladies and gentlemen, between practical math and theory.**

That just goes to show you that almost all mathematicians, deep down, are practical mathematicians.

* * *

rocks

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**Author:** ![don\_willard](https://avatars.discourse-cdn.com/v4/letter/d/a88e57/32.png) [@don\_willard](https://boards.straightdope.com/u/don_willard)\
**Post date:** [June 2, 2003, 6:28pm UTC](https://boards.straightdope.com/t/math-99repeating-1/11021/83 "2003-06-02T18:28:49Z")

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I asked the same question in another post without having done proper research in this one, because I asked the questrion without going first to this here post. Thus ignore my independent post and eliminate it as I now understand the whole thing.

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**Author:** ![John\_Kentzel-Griffin](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@John\_Kentzel-Griffin](https://boards.straightdope.com/u/John_Kentzel-Griffin)\
**Post date:** [June 2, 2003, 7:30pm UTC](https://boards.straightdope.com/t/math-99repeating-1/11021/84 "2003-06-02T19:30:09Z")

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Ummm . . . OK 😕

I’ll just close this since there is an active thread on the subject. [Why doesn’t .9999~ = 1?](http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=187902&pagenumber=2)

**DrMatrix** - GQ Moderator

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