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Math Help - Prove 1+1=2

  1. #1
    Senior Member Mukilab's Avatar
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    Prove 1+1=2

    How to prove (not show) that 1+1=2
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  2. #2
    Super Member Quacky's Avatar
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    I'm not sure I understand. There is not a proof needed. Is that not almost the very definition of two?
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  3. #3
    Senior Member nikhil's Avatar
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    Talking my thinking

    I guess 1+1=2 is a convention.
    if a single entity is called 1 (conventionally) then its double will be called 2(conventionally). since two quantities are individually single therfor 1+1=2 must hold. [for this operation of addition is also defined conventionally.]
    this question is similar to the question why B comes after A.(even it is a convention)
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  4. #4
    Senior Member Mukilab's Avatar
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    Quote Originally Posted by nikhil View Post
    I guess 1+1=2 is a convention.
    if a single entity is called 1 (conventionally) then its double will be called 2(conventionally). since two quantities are individually single therfor 1+1=2 must hold. [for this operation of addition is also defined conventionally.]
    this question is similar to the question why B comes after A.(even it is a convention)
    Quote Originally Posted by Quacky View Post
    I'm not sure I understand. There is not a proof needed. Is that not almost the very definition of two?
    not what I was looking for. Will wait for further answers.
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  5. #5
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    x+x=(x+x)=2(x)

    A unit added to a unit is two of the same unit, by definition.
    = means "what is before" is the same as "what is after".

    If x=1,

    1+1=2(1)=2

    This proof requires the definition that the "symbol" 2 represents two of the same unit,
    whatever that unit may be.
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  6. #6
    MHF Contributor Drexel28's Avatar
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