# Importance of zero

by strid
Tags: importance
 P: 77 I know that the "discovery" (rather invention) of the number zero was revolutionary and is seen as VERY important... I've always had some suspicion to the zero by some unknown reason... I decided some weeks ago to figure out what it is that is wrong with the zero... So could someone please tell me in what ways the zero is SO very important... What I've thought of yet is that the zero doesnt exist in reality but is just an invention to make stuff work.. but what?
 HW Helper Sci Advisor P: 9,395 Before you talk about existence or non-existence of zero would you care to explain what mathematical objects you think do exist and in what sense. Moreover, why are these other things you trust not also inventions "just to make stuff work"?
 P: 77 the thought I'm playing with for the moment is that every rational number has its origin in 1. So by multiplying with 2 you get 2. by multiplying with 500 you get 500. And by dividing by 2 you get 0,5. Dividing by 500 give you 0,002. So the bigger number you mulitply with the closer you approach "infinity"... but you can never "reach" it... The same way, the bigger number you divide it by, the closer you come to zero, but you can never "reach" it... so just as infinity is not a "number", zero is neither a number... EDIT: to rephrase my question... what makes zero som important in maths.. what problems did we have before we discovered the zero?
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P: 1,123

## Importance of zero

All rational numbers come from integers, where a is some integer, 0 is defined by: a + 0 = a. That's pretty much all there is to it.

In integers, rational, real and complex numbers a/0 is not a number because dividing by 0 is not defined.
 P: 77 but what is then the profit of the zero? why was the discovery of zero so revolutionary?? the 0 doesnt help us alot in a+0=a why not just skip the 0.. its useless (at least in this case)... so can anyone come up with a place where the zero is good,,..
 HW Helper Sci Advisor P: 9,395 It is the cardinal number of the empty set, it is the additive identity of the reals, etc. It is therefore important in field theory and thus all of algebra and without it and the ideas contained in the notion of identities and inverses there would be practically no modern mathematics and physics. And you'be still not said why you think 1 "exists"
 P: 77 "It is the cardinal number of the empty set, it is the additive identity of the reals, etc. " didnt understnad anything of that... could you explain one of those instead of just mentionening it.. if i have an apple i name the quantity 1... so if i have two apples i can i can do 1*2 and get 2 apples... so in that sense 1 exists.... but saying that you have 0 apples when you have nothing is not the same thing... because 0 is nothing...
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 Quote by strid if i have an apple i name the quantity 1... so if i have two apples i can i can do 1*2 and get 2 apples... so in that sense 1 exists.... but saying that you have 0 apples when you have nothing is not the same thing... because 0 is nothing...
This sounds more like a philosophical question. Is nothing something? Who knows. "0" is certainly something because we give it meaning and use it as an object, but that which it represents may actually not be something. The same would go for the word "nothing". It exists and has definition, but is a pointer to nothing.
 P: 77 then infinity? there are inifinte many points in any line... does that make infinity a number? if 0 is nothing infinty is sort of everything... they have both a mathematical value but none of them, according to me, are numbers.
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P: 1,123
 Quote by strid then infinity? there are inifinte many points in any line... does that make infinity a number? if 0 is nothing infinty is sort of everything... they have both a mathematical value but none of them, according to me, are numbers.
Give us how you define a number then?

In mathematics numbers are constructed from sets.

1 is the multiplicative identity as: 1*a=a
0 is the additive identity as: 0 + a = a

Both are highly useful.
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 Quote by strid then infinity? there are inifinte many points in any line... does that make infinity a number?
Meh, I think the definition of "number" should be left to the mathematicians, seeing that it's a mathematical concept.
 P: 77 I dont see how a+0=a can be useful... its the same thing as a=a i'vent thought through this very much but what criterias a number needs to have is at least that they can cope with the arithemtics which neither zero nor infinty does... a/0 is undifined as well as a/infinity....
 PF Patron HW Helper Sci Advisor Thanks P: 11,935 The basic reason why you don't get this, strid, is that you mix your own silly, private fantasies of numbers, and what operations you might do with them into the properly defined area of mathematics. I have a suggestion for you: 1. Start to regard your own thoughts as the dumb results born of ignorance. 2. Start learning maths properly.
 P: 77 arildno, you arguments are magnificient... are you a lawyer? I'm totally convinced that you are right and I've surely leartn something new... (in cas you dont get it, I'm sarcastic) However.... what makes zero more number than infinity? if zero is a number then infinity has to be as well... or, as i am claiming, none are...
 P: 42 I agree. Just accept the number. What did it ever do to you? In any system, like one with mathematical relations has to define what "something" is, on the contrary, it must also define what "nothing" is. Don't major in philosophy.
 PF Patron HW Helper Sci Advisor Thanks P: 11,935 "what makes zero more number than infinity? if zero is a number then infinity has to be as well... or, as i am claiming, none are..." Why? How should I know what idiotic personal thought-process has lead you to this result? It certainly hasn't anything to do with maths or logic. Since you show an active unwillingness of actually learning anything, here's a new suggestion: Keep your private mental jerk-offs to yourself.
 P: 42 Its only more practical to treat zero more like a number. Do we ever say "I have infinity apples?" It makes sense to say that I have zero apples. Plus, we use infinity usually to see how something behaves (something like a series) as it approaches infinity. We even do the same thing with zero (at least not with series)
 P: 42 This isn't going anywhere

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