Is 3/3 the same as 1 or not? The Confusion Between Decimal Notation and Numbers

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Discussion Overview

The discussion revolves around the equivalence of the decimal representation 0.9999... and the number 1, particularly in the context of fractional representations such as 1/3 and 3/3. Participants explore the implications of decimal notation versus numerical values, touching on concepts of equality in mathematics.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that since 1/3 equals 0.333..., then 3/3 should equal 0.9999..., leading to the question of whether 0.9999... is the same as 1.
  • Another participant asserts that 0.9999... is indeed the same as 1, providing examples of different representations of the same number, such as 1/2 and 3/6.
  • A further reply emphasizes that the confusion often arises from misinterpreting decimal notation as distinct from the actual numbers they represent.

Areas of Agreement / Disagreement

Participants express disagreement regarding the equivalence of 0.9999... and 1, with some asserting they are the same and others questioning this equivalence.

Contextual Notes

Participants highlight the potential for confusion between decimal notation and numerical values, suggesting that this may stem from differing interpretations of mathematical representations.

dracobook
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My friend thought of this some time ago...
1/3 is equal to .333333...
2/3 is equal to 2*(1/3) or .66666...
3/3 is equal to 3*(1/3). If 1/3 is equal to .333... then wouldn't 3/3 be equal to .9999...? Also, isn't .9999... not the same as 1?
 
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You should search this. Analogues of this question have come up before.
 
Also, isn't .9999... not the same as 1?

Double negatives! I don't think you're asking quite what you meant to ask. :biggrin:

0.999~ is the same number as 1. That the same number can have different symbolic representations shouldn't be surprising... after all, you know that the fractions 1/2 and 3/6 are the same number!

Examples like the one you posted are demonstrations of why mathematicians decided to require that 0.999~ = 1 in the decimal number system: otherwise arithmetic would not work nicely.
 
Hurkyl said:
Double negatives! I don't think you're asking quite what you meant to ask.

Actually, Hurkyl, reading the whole post I think this time the double negative was exactly what he meant. Many people who confuse the "decimal notation" for numbers with the numbers themselves think that 0.9999... is not 1. Here I think the OP was saying: "Isn't it the case that 0.9999... is not the same as 1" and the double negative is perfectly correct.
 

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