3 ms·
I'm kind of more intersted in why you know this. There's lots of weird esoteric stuff that I know that I need as part of my job, but what are you doing that req
by Traster 5y ago
I'm kind of more intersted in why you know this. There's lots of weird esoteric stuff that I know that I need as part of my job, but what are you doing that requires you to know this that isn't "copy paste this number into a python notebook"?
Oh and if you are copy pasting into notebook, then x %7 == 0 probably is a reasonable substitute...
- lurquer 5y agoI can’t speak for the poster, but I learned that trick (and many others) to play a game while stuck in traffic. Namely, derive the prime factorization of the license plate number in front of you before you lose sight of it. (Usually a 5 digit number in my area.) Sort of silly, but it passes the time.
- jldugger 5y agoI mean, who isn't loading their Anki decks with random mental math party tricks?
- meiji163 5y agoIt's just the fact that 1, 10, 100, 1000, ... = 1, 3, 2, -1, -3, -2, ... (repeating) mod 7
- tashi 5y agoI test numbers for divisibility by 7 in my head almost every time I do a daily KenKen puzzle. There's usually a four or five-digit number in there whose factors I don't know off the top of my head, so I'll give it a quick check for sevens just to get my bearings. But a python notebook could definitely beat me in a race.