1 = 99

Here’s an oldie you may have come across once or twice in your mathematical travels.

Can you prove that 1 = 99?

Sure you can.

But, to prove this obvious erroneous statement, you need to start with one that’s equally considered erroneous.

Consider the statement 2 + 2 = 5. Humor me for a moment, and forget the obvious falsehood of that conclusion. In fact, I want you to use it as your starting point.

There! Now prove 1 = 99.


…



Starting point:

2 + 2 = 5

Condense:

4 = 5

Subtract 4 from each side:

4 – 4 = 5 – 4

Condense:

0 = 1

Multiply each side by 98

0 x 98 = 1 x 98

Condense:

0 = 98

Add 1 to each side:

1 = 99

There! Q. E. D!


Obviously, you can prove 1 = any number n when you begin with 2 + 2 = 5 (or any such similar erroneous equation resulting in 0 = 1). Just multiply the 0 = 1 by (n – 1) and then add 1 to the result.

Just one more reason, I guess, to make sure you teach Little Johnny how to do his sums in grade school.

Also, doesn’t your stomach feel a little queasy manipulating all these incorrect equations?

Hmmm?