Mathematical Craziness.

So, anyone here ever heard of the fact that .999... is equal to 1?

Just in case you haven't, it's true.

I love having this discussion with people, so if you don't agree with me, or would like some proofs, please post away. I love mathematical debates.

Haha.

You're just looking for an argument aren't you? Sadly, I cannot give you to you here as there is little room for interpretation.

.999 repeating does indeed equal 1.

So would it equal 1% etc?

I don't understand your question combo? 1% is the same as .01. I do not know how that relates to .999 repeating equaling 1.

Oops. I made a mistake there. Well I meant to say what percentage does .999 equal? 100%

1.0 is equal to 100%.

.999 repeating is equal to 1.0.

Therefore, .999 repeating is equal to 100%

screw school ill come back here in two days...
math=school

.999 repeating = 1.0
not .999 by itself

yes you have to make sure that you either say .999.... or if you can put the line on top making it repeating, but .999... does equal 1

isn't that the thing that says since 1/9 is 111111111111......... and 2/9 is 2222.... and so on and so forth that 9/9 would equal 99999..... and also 1.

9/9=9÷9=1
But 9999 repeating still is 1...

Tony90908 wrote:

9/9=9÷9=1
But 9999 repeating still is 1...

Yeah I know that 9/9=1 but my 7th grade substitute teacher was trying to say that because 1/9 is .1 repeating and 2/9 is .2 repeating and so on so forth that it is almost like 9/9 is .9 repeating.

Well its
1/9=.11111...

but then you get down to

8/9= .8888888...
and then

9/9= .999999999....=1

godlubsm wrote:

Tony90908 wrote:

9/9=9÷9=1
But 9999 repeating still is 1...

Yeah I know that 9/9=1 but my 7th grade substitute teacher was trying to say that because 1/9 is .1 repeating and 2/9 is .2 repeating and so on so forth that it is almost like 9/9 is .9 repeating.

Zach already replied to this, but I wanted to confirm.

9/9 is .999 repeating. This is one of the simplest, basic math ways to show that .999 repeating is equal to 1.

Blaeu wrote:

Haha.

You're just looking for an argument aren't you?

Maaaayyyybeee....


Anyway, Woo! Responses!

Also: Woo! People that know what they're talking about!
It's awesome to finally be able to say this to other people without having seven idiotic 13-year-olds yell at me for saying something that sounds controversial to them, and give me no reasons for .999... not being equal to 1 other than "Because they're different numbers! You're stupid! Don't you know math!?".

Proofs that .999... is equal to 1, in case anyone would like to know more:

Proof #1:

1/3= .333...
2/3= .666...
3/3= .999... and 1.

(Numbers can have multiple ways of writing them out, usually in different formats. However, .999... is the exception, because it has two very different-looking ways of writing it in decimal form, as well as being able to right it out in fraction and percentage form.)

Proof #2:

Let x = .999...
10x = 9.999...
(-x -x)
9x=9.0
(/9 /9)
x = 1
.999 = 1

(Algebra can also prove the fact. For some reason, if I show this proof to any of my friends, they say that it doesn't count because I'm manipulating numbers to prove the point. However, all of Algebra is about manipulating numbers to show a more simple equation. Apparantly, according to that argument, anything proved using Algebra is incorrect, as you have to manipulate the numbers and variables to make a more concise and clear equation.)

Proof #3:

I'm not one of these people, but many claim a number to be equal to another if there are no numbers in between the two. You could also state this by saying "For every two different numbers, there is a third number that is between them".
By that argument, .999... is equal to 1 because nothing is between .999... and 1.
"But, you can't say that! There has to be something between the numbers!"
No, that's not true. The "..." means "goes on forever", or "infinitely expanding". You can't have a number after forever. It just doesn't happen.

Proof #4:

Pretty much the quickest mathematical proof.
If the difference between two numbers is zero, then they must be equal. For example, 5 - 5 = 0 because 5 = 5.
What do you get if you subtract .999... from 1?
1.000... - 9.999... = 0.000...
= 0

Therefore, the two are equal.

There's a ton more proofs, but these four seem to me to be the quickest, and most easily understanded proofs.

Again, thanks for the replies, and if you have any more questions, feel free to say so, or to question these proofs.