## Monday, May 20, 2013

### Parity of Zero

Did you know: As much as half the population doesn't know that zero is an even number? And that this can cause problems in cases like gas-rationing based on license plates' last digit (as happened here in NYC last fall after Hurricane Sandy).

http://en.wikipedia.org/wiki/Parity_of_zero

#### 2 comments:

1. Numbers parity

Any number, except zero, multiplied twice, is an even number.
A pair has two elements.

Demonstration:

One multiplied twice, result is a pair.
A pair has two elements.

Two multiplied twice, result is two pairs.
Zero exception:

Zero multiplied twice, resulting zero pairs.
Zero pair has zero elements, therefore:

The number zero is neither odd nor even.

Conclusion:

The smallest odd number is one.
The lowest even number is two.
The number zero is neither odd nor even.

The classic definition:

necessary condition,
(NOT SUFFICIENT CONDITION,)
to determine whether a number is even,
to be divisible by two.

Original link http://gvitalie.github.io/zero/

1. Ha, that's pretty lunatic. I'll leave it here for laughs.

Of course, the key gap is to leave a blank where the definition should go. Math is always about starting with a careful definition.