Proof that 1 = 2

Here’s an “interesting” proof I came across. Get ready to rethink everything you knew about Maths:

Given x = 1 and y = 1, then

x = y

Multiplying each side by x,

x2 = xy

Subtracting y2 from each side,

x2y2 = xy – y2

Factoring each side,

(x + y)(x – y) = y(x – y)

Dividing out the common term, (x – y) results in

x + y = y

Substituting the values of x and y,

1 + 1 = 1


2 = 1



  1. Nice try, but x^2 does not equal x time y, it equal x times x. you can’t back and forth between using the variables (x and y) and assigning values to those variables, until you have completed the algebra.

  2. Proof that a horse has an infinite number of legs:

    A horse has fore legs and back legs.
    But fore legs plus two back legs equals six legs, and this is certainly an odd number of legs for a horse to have. But six is an even number, so the horse has an odd number and even number of legs at the same time. The only number that can be even and odd at the same time is inifinity, therefore a horse has an infinite number of legs.

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