From mathforum.org: http://mathforum.org/dr.math/faq/faq.false.proof.html And another: "Proof": 2 = 1 a = b a2 = ab a2 - b2 = ab-b2 (a-b)(a+b) = b(a-b) a+b = b b+b = b 2b = b 2 = 1 What is wrong with this proof? Well, the fact that we got 2 = 1 is proof that the method of getting the solution was not mathematically sound. (Read a detailed discussion and find the fallacy in our archives.) -----Original Message----- From: Paul_Lemonidis@xxxxxxxxxxx [mailto:Paul_Lemonidis@xxxxxxxxxxx] Sent: Thursday, August 12, 2004 11:36 AM To: [ISAserver.org Discussion List] Subject: [isalist] Re: XP HOME http://www.ISAserver.org If I remember correctly from my school days there is a very dodgy mathematical proof that 1=2? Thus if 1+1=2 it also stands to reason that since 1+2=3 that 1+1=3.