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submitted 3 months ago* (last edited 3 months ago) by booly@sh.itjust.works to c/showerthoughts@lemmy.world

Amazon is running a Prime Day sale on July 16 and 17. Setting aside the fact that this is two separate days, neither 716 nor 717 are prime numbers. They should've done 7/19 instead.

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[-] Audacious@sh.itjust.works 2 points 3 months ago

Back in the olden days before digital calculators, people had tricks like that to help them do mental math.

[-] FeatherConstrictor@sh.itjust.works 1 points 3 months ago

๐Ÿ˜‚ I'm familiar with many of them because I liked math in school and went through all of primary and middle school without a digital calculator. This one is one I hadn't heard of before and, again because I like math, I'm interested in understanding 1) what the trick is and 2) mathematically how it works out

this post was submitted on 17 Jul 2024
255 points (93.2% liked)

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