[CardCarryingMember.VastRightWC]

Here's a slightly less complex version of it:

Given a=b, prove that 1=2.

PROOF:

      a   =   b          Given
    a*b   =   b^2        Multiply both sides by b
a*b - a^2 = b^2 - a^2    Subtract a^2 from both sides
   a(b-a) = (b+a)(b-a)   Factor
      a   =   b+a        Divide both sides by (b-a)
      a   =   2*a        Since a=b as originally given
      1   =   2          Divide both sides by a

[phantomworker]

Of course you know your assumption is faulty. a cannot equal b in an ordered set of numbers.