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1. Ute Hauth (miradlo@pirati.ca)'s status on Sunday, 29-Apr-2018 14:06:43 EDT Ute Hauth
   ♲ @Vincent Pantal🍩ni (panlepan@twitter.com): (a+b)²=a²+2ab+b²
   
   pbs.twimg.com/media/Db5JE_9WsA…
   
   1. СтаЛьг (staleg@loadaverage.org)'s status on Sunday, 29-Apr-2018 15:06:37 EDT СтаЛьг

      in reply to
      @miradlo since that, it equals to a²+b(2a+b) (the core formula for manual sqrt method, if anyone remembers it).
      …
      Moreover, if the first number can be assigned as 10a, and b=5, we'd got:
      (10a+b)² = 100a²+20a•5+25=100a(a+1)+25.
      Hence, to square any [two-digit] number ending by 5, you should multiply number of tens with one added with 1, and write 25 after that. So, 75²={7·8=56}= 5625.
      …
      Enjoy! 😜
      #mathhack
   2. Ute Hauth (miradlo@pirati.ca)'s status on Sunday, 29-Apr-2018 17:30:36 EDT Ute Hauth

      in reply to
      Thanks, that's cool!