Wednesday, June 9, 2010

Count to 1,023 on your fingers (spoiler: it's finger binary!)

I just had the epiphany that normal finger-counting is in unary. It's like binary, but lower! For some reason, even though "binary" indicates "2" I never realized there could be a counting system below that. It's not complicated though. Unary is just what you use when you count with tally marks ( or ).

So I realized instead you can use binary! Cause your fingers can represent 0 or 1, right? And that should totally let you higher than 10. Who hasn't run out of fingers sometimes? And then I tried to figure out how high that lets you count. Since you have 10 fingers and each is a binary digit you can go to 210-1, which equals... 1,023. Whoa.

Then I tried it out to make sure and see how easy it is to do. It gets a little weird. Here's an idea:

So there you go! Perhaps with some practice counting this way will be natural enough to be actually useful!

And in the interests of internet ethics, I will credit my source for this idea. A really esoteric source: this comment on a Boing Boing post where a guy mentioned, in passing, counting on his fingers in unary vs. binary.

(For further reading, I'll let you know there's (of course) a Wikipedia article.)


  1. You count in denary not unary because you still use ten as your base. Also your image of binary 124 is wrong . Its 220. 124 would be thumb on the right hand middle finger on the left.

    1. Well, if you go by the orientation in the picture, you get 0xDC (11011100), which is 220. But that's not the standard. The standard is to face your palms toward yourself. So the way to get this number would be to mimmick his hands, then face your hands towards yourself, THEN record it. You get 0x187 (110000111), which is...391. So nobody was correct.

    2. nobody is correct indeed if the thumb is the least significant bit in binary we should keep that convention meaning the thumb on the other hand should be 32 and double from there, hence it would be 199

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