One of the Oldest Math Tricks

January 17th, 2010 by admin | Filed under Math Tricks.

Many of you may have seen this one before – it is very old (I first saw this in grade school, which makes this example of math tricks ancient!).

Yes, it is the infamous 2=1 “proof”.  Here I present it to you as a graphic an also as a video set to Beethoven’s 5th (yea – it was raining yesterday so I had a lot of time on my hands!).

First, here is the graphic of the proof:

And now for the video proof:

So that is the proof.  Can you spot where the error is?

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Tags: 2=1, math proof, Math Tricks

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4 Responses to “One of the Oldest Math Tricks”

1. Marco | 19/01/10

   By the first line: A=B => A-B=0

   …
   (A+B)(A-B) = A(A-B)

   You can’t divide by (A-B), you can’t divide by 0!

2. mike | 9/02/10

   as said a-b never cancelled bcoz a-b=0 and 0 never cancels other 0

3. Ryan | 10/02/10

   don’t call it a proof. it’s not a proof.

4. masaru shinoda | 9/03/10

   ahahahahaha.. it’s a nice trick.. ^_^v

   if A=B

   so, A-B = 0 right.?

   therefore: => (A+B)(A-B) = A(A-B)

   => (A+B)(A-B) = A(A-B)
   ——– —-
   (A-B) (A-B)

   => Let us A=2 and B=1; therefore; (A-B) is (2-1)
   => so the A-B = 0

   => the solution must be undefine…

   …………………………..♣cUtEmAntsAnG♣………………

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