# Does .999999 = 1 vPOLL **URL:** \ **Category:** NYSpeed Off Topic\ **Created:** [June 20, 2006, 8:06am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546 "2006-06-20T08:06:47Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![badazzss](https://avatars.discourse-cdn.com/v4/letter/b/e19adc/32.png) [@badazzss](https://forums.speedlife.net/u/badazzss)\ **Post date:** [June 21, 2006, 1:40pm UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/101 "2006-06-21T13:40:01Z")
yes. in reality - yes it does. does it make a difference - no. so, are .999~ and 1 the same number? in reality - no. does it make a difference - only on internet forums. lol ---
**Author:** ![badazzss](https://avatars.discourse-cdn.com/v4/letter/b/e19adc/32.png) [@badazzss](https://forums.speedlife.net/u/badazzss)\ **Post date:** [June 21, 2006, 1:56pm UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/102 "2006-06-21T13:56:23Z")
here you go… any number multiplied by 1 is itself, right? so, 1 x 1 = 1. 2 x 1 = 2. 5,837,279 x 1 = 5,837,279. now try multiplying those numbers by .999~. can’t really do it. and even at your best approximation, the number comes back skewed in the decimal. at SOME point in the number, there will be a digit that is no longer 9. the same works with dividing by 999~. you can’t use the argument that .999~ goes on forever and that would never happen, because unlike the math “proofs”, you can’t physically do the math and prove it. ---
**Author:** ![Dr.Stevil](https://avatars.discourse-cdn.com/v4/letter/d/da6949/32.png) [@Dr.Stevil](https://forums.speedlife.net/u/Dr.Stevil)\ **Post date:** [June 21, 2006, 2:10pm UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/103 "2006-06-21T14:10:09Z")
> [@Itagaki](#): > > I’m not a math major here, but its a matter of .999 being a repeating decimal. > > Joe and others have given the basic formulas and logical explinations. I myself can’t even begin to formulate a reason, my head hurts too much already and this week (all 3 days of it) has been a living hell and I don’t feel like explaining myself. > > Bout how bout this: if 0.333…34 is used as a decimal representative of 1/3 (instead of 0.3333~), then what would you do with 0.99999~? If you round the last decimal place up, as you should, you would end up with 1. > > Like I said, my head hurts too much right now. lol I hear ya… I was honestly wondering if anyone knew the answer 😃 I was just curious edit: ACTUALLY… I guess, if your not using 10 (aka start from zero and up opposed to starting from one) than that totally makes sense I guess. Because .999~ would be the highest number you could hit before going back to 0 (0,1,10,ect) ---
**Author:** ![SubaruDan](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/subarudan/32/7195_2.png) [@SubaruDan](https://forums.speedlife.net/u/SubaruDan)\ **Post date:** [June 21, 2006, 4:51pm UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/104 "2006-06-21T16:51:32Z")
> [@badazzss](#): > > its been awhile since i’ve done math… but… how do you get from: > > - x = -0.999… > to > 9x = 9.000… = 9 > ? > > to get from - x = - 0.9999~ to the next step, you would have to multiply both sides by -9. when you do so, you can’t multiple -9 by -0.9999~ because it will only give you an approximate #, it will NOT give you 9. it’s impossible to multiply that without rounding. > > and like sureshot said, 1/3 does not equal .3333~ > > 1 does NOT equal 0.9999~ there is a place for 0.9999~ on the number line, and it is IMMEDIATELY TO THE LEFT of 1.0. > > /thread. you arent going from - x = -0.999… to 9x = 9.000… = 9 you start with 10x = 10.999… then you subtract x from each side, and get 9x = 9.000… = 9 edit: I dont want it to seem like me helping someone with the math to prove .99… = 1 means that I believe it. I still dont, and I still like my argument. My favorite number is the number i… ---
**Author:** ![JoesTypeS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/joestypes/32/7190_2.png) [@JoesTypeS](https://forums.speedlife.net/u/JoesTypeS)\ **Post date:** [June 21, 2006, 6:19pm UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/105 "2006-06-21T18:19:24Z")
> [@SubaruDan](#): > > 10x = 10.999… 10x = 9.99999… > [@badazzss](#): > > now try multiplying those numbers by .999~. can’t really do it. and even at your best approximation, the number comes back skewed in the decimal. at SOME point in the number, there will be a digit that is no longer 9. the same works with dividing by 999~. > > it. You can’t do it b/c you can’t multiply on a traditional calculator by an infinitely repeating number… ---
**Author:** ![FightinMike](https://avatars.discourse-cdn.com/v4/letter/f/7bcc69/32.png) [@FightinMike](https://forums.speedlife.net/u/FightinMike)\ **Post date:** [December 7, 2006, 1:56am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/106 "2006-12-07T01:56:02Z")
> [@sureshot007](#): > > Are you saying that Windows is wrong??? Actually yes, in the sense that any machine using an IEEE 754 Floating Point Standard is wrong. Windows uses double precision or 64 bits to store a number in binary format. Since quite often mathematical operations exceed 64 bits in length there must be action taken to fit the number into a base10 representation of that value. Option 1) chop the bit, like it never existed. Not used in IEEE 754. Option 2) round the 64th bit, based on the 65th bit. In binary if the 65th bit is a 1 round up. This is what is used in IEEE 754 and leads to what is called cascading catastrophic error. For a more in depth answer, look for my post here:[http://www.nyspeed.com/forums/showthread.php?t=22279](http://www.nyspeed.com/forums/showthread.php?t=22279) ---
**Author:** ![LAFENGAS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/lafengas/32/7573_2.png) [@LAFENGAS](https://forums.speedlife.net/u/LAFENGAS)\ **Post date:** [December 7, 2006, 5:36am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/107 "2006-12-07T05:36:32Z")
ugh, i don’t want to get into this, but the correct answer would be circumstantial. A little bit of engineering background first. Anytime something thats engineered and affects human safety has a “Factor of Safety” applied to it. A Saftey factor of 1 means that is the minimum design for load and a safe operation providing it’s a perfect world and there are no defects in material, workmanship, mother nature, etc. That being said, If I were engineering a bridge that every one of you had to cross over would you cross it if you knew it only had a safety factor of .9999? In my world, .9999 and 1 are a completely different. Figures don’t lie and liars can figure. ---
**Author:** ![brent\_strong](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/brent_strong/32/7203_2.png) [@brent\_strong](https://forums.speedlife.net/u/brent_strong)\ **Post date:** [December 7, 2006, 5:52am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/108 "2006-12-07T05:52:28Z")
Yes, .9999 and 1 are different. .99999… and 1 are not. You would not be able to use .9999… as written in your calculations, since you cannot terminate the expansion of the number and have it still be .9999… To you, .9999… is useless. 1 is the representation you need and can use. ---
**Author:** ![Fry](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/fry/32/7284_2.png) [@Fry](https://forums.speedlife.net/u/Fry)\ **Post date:** [December 7, 2006, 6:18am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/109 "2006-12-07T06:18:16Z")
It does not EQUAL 1. It APPROACHES 1 as the number of decimals approach infinity. OK, now i’ll go back and read the whole thread to find out why that’s so fucking hard… ---
**Author:** ![Fry](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/fry/32/7284_2.png) [@Fry](https://forums.speedlife.net/u/Fry)\ **Post date:** [December 7, 2006, 6:40am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/110 "2006-12-07T06:40:41Z")
Oh sweet effing Jesus. You all are victims of a high school math teacher’s trick. Remember way back in the day when you had to check your algebra by doing it in reverse? Lets see if we can get back to .999~ x=1 9x=9 10x=10 10x-9x=10-9 x = 1 Oops! No .9999999~ in there. Your math doesn’t check out! :eyebrow: It’s a cute trick but .999~ is a fucking number. It is a number that approaches 1 forever. It is not 1. It gets closer and closer and closer until the end of time but it is never equal to 1. ---
**Author:** ![LAFENGAS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/lafengas/32/7573_2.png) [@LAFENGAS](https://forums.speedlife.net/u/LAFENGAS)\ **Post date:** [December 7, 2006, 6:42am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/111 "2006-12-07T06:42:22Z")
**Agreed, the algebra is correct. Unfortunately, 1 simply does not equal 0.999… Like Spock Says, it’s Illogical. (Even though tricks with numbers seem to show it as equal). In calculus, i remember lines that became asymptotic to another line. So 0.999… is becoming asymptotic to 1, but will “never” reach it therefore 1 is not equal to .999… It becomes “Infinitely close” to 1, but never reaches it. It’s just that simple, no matter what algebraic tricks are played.** ---
**Author:** ![Zer0DazE](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/zer0daze/32/7624_2.png) [@Zer0DazE](https://forums.speedlife.net/u/Zer0DazE)\ **Post date:** [December 7, 2006, 6:51am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/112 "2006-12-07T06:51:55Z")
> [@LAFENGAS](#): > > It’s just that simple, no matter what algebraic tricks are played what about jedi mind tricks? ---
**Author:** ![LAFENGAS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/lafengas/32/7573_2.png) [@LAFENGAS](https://forums.speedlife.net/u/LAFENGAS)\ **Post date:** [December 7, 2006, 6:57am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/113 "2006-12-07T06:57:04Z")
> [@Zer0DazE](#): > > what about jedi mind tricks? i’m not into scientology. ---
**Author:** ![raven](https://avatars.discourse-cdn.com/v4/letter/r/9fc348/32.png) [@raven](https://forums.speedlife.net/u/raven)\ **Post date:** [December 7, 2006, 9:27am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/114 "2006-12-07T09:27:46Z")
Where is the answer “It will land on the surface of Mars”? ---
**Author:** ![Ninja](https://avatars.discourse-cdn.com/v4/letter/n/53a042/32.png) [@Ninja](https://forums.speedlife.net/u/Ninja)\ **Post date:** [December 7, 2006, 10:09am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/115 "2006-12-07T10:09:41Z")
![http://polymathematics.typepad.com/photos/uncategorized/9s_algebra](http://polymathematics.typepad.com/photos/uncategorized/9s_algebra) Editing… ---
**Author:** ![Zer0DazE](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/zer0daze/32/7624_2.png) [@Zer0DazE](https://forums.speedlife.net/u/Zer0DazE)\ **Post date:** [December 7, 2006, 10:47am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/116 "2006-12-07T10:47:32Z")
> [@LAFENGAS](#): > > i’m not into scientology. fancy card and coin tricks? or the trick where someone taps you on the shoulder on the opposite side… then you look, but theres no one there. i bet that trick would fool you into believing ---
**Author:** ![boardjnky4](https://avatars.discourse-cdn.com/v4/letter/b/96bed5/32.png) [@boardjnky4](https://forums.speedlife.net/u/boardjnky4)\ **Post date:** [December 7, 2006, 10:57am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/117 "2006-12-07T10:57:36Z")
i agree with LAFENGAS and BikerFry ive taken too many college level math courses to be convinced that .9999999999999 = 1 it gets ever so close to 1, but not quite. ughh now u guys have me thinking about limit graphs and shit with empty spaces… ahhhhhhh horrible calculus flashbackss!!! make it stop!!! …all better ---
**Author:** ![Fry](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/fry/32/7284_2.png) [@Fry](https://forums.speedlife.net/u/Fry)\ **Post date:** [December 7, 2006, 11:22am UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/118 "2006-12-07T11:22:45Z")
![http://polymathematics.typepad.com/photos/uncategorized/9s_algebra](http://polymathematics.typepad.com/photos/uncategorized/9s_algebra) That is where the “trick” or, as I like to call it, the mathematical error lies. That equation was not solved correctly. That equation cannot be solved for a real number. 9.99~ and .99~ both have decimal places that go on for infinity. They are not real numbers. 9.99~ - .99~ is not = 9. It is equal to a number infinitely close to 9, but it is not a real number. So while this is a cute trick of algebra, it is based on one false assumption: That you can solve infinity - infinity and get a real number. You cannot, as infinity is not a real number. [http://mathforum.org/library/drmath/view/57069.html](http://mathforum.org/library/drmath/view/57069.html) [http://www.galactic-guide.com/articles/8R69.html](http://www.galactic-guide.com/articles/8R69.html) ---
**Author:** ![FightinMike](https://avatars.discourse-cdn.com/v4/letter/f/7bcc69/32.png) [@FightinMike](https://forums.speedlife.net/u/FightinMike)\ **Post date:** [December 7, 2006, 12:03pm UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/119 "2006-12-07T12:03:40Z")
cant we just agree that it doesnt equal one, but machines still arent “smart” enough to realize it? And I do agree with you BikerFry that the algebra is a bit of trickery. However you saying that it isnt a real number is false. Any non-terminating infinitely repeating decimal is a rational number and therefore a real number. ---
**Author:** ![Fry](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/fry/32/7284_2.png) [@Fry](https://forums.speedlife.net/u/Fry)\ **Post date:** [December 7, 2006, 12:31pm UTC](https://forums.speedlife.net/t/does-999999-1-vpoll/13546/120 "2006-12-07T12:31:49Z")
> [@FightinMike](#): > > However you saying that it isnt a real number is false. Any non-terminating infinitely repeating decimal is a rational number and therefore a real number. You’re right. My terminology is incorrect. As you stated, a repeating decimal is actually a real and rational number: [http://en.wikipedia.org/wiki/Recurring\_decimal](http://en.wikipedia.org/wiki/Recurring_decimal) My little bit of research to verify the terminology also reinforced that the error in the “proof” is in (9.99999~ - .99999~) = 9. It is not correct, it is undefined. See here: [http://en.wikipedia.org/wiki/Infinity#Undefined\_operations](http://en.wikipedia.org/wiki/Infinity#Undefined_operations) > [@FightinMike](#): > > cant we just agree that it doesnt equal one, but machines still arent “smart” enough to realize it? :word: No it’s not equal to 1. Yes for all practical purposes it can be treated as 1. [Previous page](https://forums.speedlife.net/t/does-999999-1-vpoll/13546.md?page=5) [Next page](https://forums.speedlife.net/t/does-999999-1-vpoll/13546.md?page=7)