tell me about the games and tiny, specific, complex goals you invented as a child to keep from dying of boredom
I'll list some of mine
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prime factorize numbers in my head. i used to just pick random numbers i saw around esp. at math competitions. picked up some useful mental math tricks this way
oh i also used to insist on crossing sidewalks and stuff in a checkerboard pattern wrt any lines in the ground but i think stuff like that is pretty common?
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the main mental math trick is to check divisibility by repeatedly subtracting large multiples of the number. like check divisibility by 7 by repeatedly subtracting e.g. 70, 1400, 4900, etc. also the reverse, like subtracting into (or allowing negatives)
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gdi I never did figure out a trick for 7s!!!!
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I mostly just made/make equations with the basic arithmetic operators on the digits.
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I still do this.. I also find large numbers (say phone numbers or credit card numbers) mod 17 in ~ 10 seconds 🙈
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ayyy nice
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