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Proof that 495 = 499.5!

  1. Jul 10, 2010 #1
    Sorry, I typed the wrong thing in the title, I meant 495.5 = 495

    (1/3) + (1/3) + (1/3) = 1
    (0.333333333333) + (0.33333333333) + (0.33333333333) = 1
    0.999999999999999 = 1
    99.9999999 = 100 (Multiplied by 10)
    99.1 = 99 (Subtracted 0.9)
    495.5= 495 (Multiplied by 5) <---------------PROOF
     
  2. jcsd
  3. Jul 10, 2010 #2
    Operations on infinite decimal representations need to be considered more carefully.
     
  4. Jul 10, 2010 #3

    Office_Shredder

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    This is not how subtraction is done

    100-.9=99?

    99.9999999... -.9=99.1?

    Both wrong. Even if we assume that you flipped the equation so 100-.9=99.1, 99.99999-.9 is not 99
     
  5. Jul 10, 2010 #4
    The second one is right.
     
  6. Jul 11, 2010 #5

    Mentallic

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    Umm... both 100-.9=99 and 99.999...-.9=99.1 are wrong. So I don't know what you're on about, plus it would've been a lot easier for the reader to determine which "second one" you're talking about by quoting just the relevant equality, not the entire post.
     
  7. Jul 11, 2010 #6

    disregardthat

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    No, 99.9999...-0.9 = 99.0999... = 99.1 is correct.
     
  8. Jul 11, 2010 #7

    uart

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    There was nothing wrong with what Werg said. Yes [itex](99.9999... - 0.9)[/itex] really is equal to 99.1.

    I cant believe this senseless OP is going to come back to yet another [itex]0.9999... \neq 1[/itex] debate. :confused:
     
  9. Jul 11, 2010 #8

    Mentallic

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    Oh yes of course, I didn't even stop to think about it once I saw all the recurring decimal places were cut off.
     
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