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.

  • @[email protected]
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    25 months ago

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

    • @[email protected]
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      15 months ago

      😂 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