## It’s Half-Past a Binomial Coefficient!

Regular numbers? Those are for amateurs. Show off your mathematical prowess with a watch that features the equivalent notation of each number.

“Awesome” should be the world you’ll hear the most while wearing this watch. And wait! It looks even better in person than in the online pictures. For \$65 it seems a bargain!

Unfortunately this Made in China watch is not particularly well constructed if we belive the online product reviews.  Several buyers complain the weakness of the mechanism and the band. Also in humid weather some moisture can condensed under the crystal wich is too bad since the watch is not water-proof.

## The Cheat Sheet! (included with each watch):

1 – Legendre’s constant is a mathematical constant occurring in a formula conjectured by Adrien-Marie Legendre to capture the asymptotic behavior of the prime-counting function. Its value is now known to be exactly 1.
2 – A joke in the math world: An infinite number of mathematicians walk into a bar. The first one orders a beer. The second orders half a beer. The third, a quarter of a beer. The bartender says, “You’re all idiots,” and pours two beers.
3 – A unicode character XML “numeric character reference.”
4 – Modular arithmetic, also known as clock arithmetic, is a system of arithmetic for integers, where numbers “wrap around” after they reach a certain value. The modular multiplicative inverse of 2 (mod 7) is the integer /a/ such that 2*/a/ is congruent to 1 modulo 7.
5 – The Golden Mean…reworked a little.
6 – Three factorial (3*2*1=6)
7 – A repeating decimal that is proven to be exactly equal to 7 with Cauchy’s Convergence Test.
8 – Graphical representation of binary code.
9 – An example of a base-4 number, which uses the digits 0, 1, 2 and 3 to represent any real number.
10 – A Binomial Coefficient, also known as the choose function. 5 choose 2 is equal to 5! divided by (2!*(5-2)!)
11 A hexadecimal, or base-16, number.

Via: Uncommon Goods

This post is also available in: French