Spooky numerology

Here’s a spooky game to play on Friday: Choose any two digit number you like. That is, think of a number that can be expressed like this

10a + b

where a and b are both single digit numbers. Now add a and b and subtract that sum from your original number, like so:

(10a + b) – (a + b)

I am now going to think about your number. Hmmm. Let’s see.

(10a + b) – (a + b) = (10a – a) + (b – b) = 9a

I need perfect silence while I meditate upon the nature of your number… it is… wait, it’s getting clearer now… it is DIVISIBLE BY 9! Pretty spooky, eh? No? Hey, where is everybody going?

Before you run away, go look at this site. milaadesign wizardry. It’s an extremely well-done version of this old mathematical chestnut. They’ve employed some very clever showmanship to obscure the simple math that I spelled out above. First, there is the creepy sound and imagery. The fact that, as an Iranian design firm, they also show the instructions in Farsi just deepens the sense of mystery. But the best hack is the last one. On the last screen you look at a big table of occult-ish symbols and pick out the one next to your number. It looks like all the symbols are different, and after a dramatic pause just long enough for some sort of telepathic voodoo, they reveal your symbol, amid chirping crickets and maniacal cackling. You didn’t have enough time to observe that all the multiples of 9 (i.e. 18, 27, 36, and so on) have this exact same symbol. Finally, for better dramatic effect, they change this symbol the next time you play.

That’s good show business! My hat is off to anyone who can squeeze that much mileage out of a two-bit math hack. (thanks to my sister-in-law Elizabeth for forwarding this one to me)

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