1=2:

OpinionJournal’s Best of the Web repeats an old math gag:

Let a=1

Let b=1

Therefore a=b

Multiplying both sides by a gives a^2=ab

Subtract 1 from the left and b (which equals 1) from the right: a^2-1=ab-b

If you remember your quadratic equations, this factors to: (a+1)(a-1)=b(a-1)

Dividing both sides by a-1, we have a+1=b, or 1+1=1

Therefore 2=1

Persuades me!

(Click here for the explanation.)