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userbinator on Feb 3, 2023 | parent | context | favorite | on: Estimating square roots in your head

I learned this method of calculating square roots to arbitrary precision and could probably easily produce 5-6 significant digits in my head if I concentrated enough:

       5. 7  4  4  5  6
      33.00 00 00 00 00
      25 = 5 * 5
       8 00
       7 49 = 10 7 * 7
         51 00 
         45 76 = 114 4 * 4
          5 24 00
          4 59 36 = 1148 4 * 4
            64 64 00
            57 44 25 = 11488 5 * 5
             7 19 75 00
             6 89 34 36 = 114890 6 * 6
               30 40 64

DangitBobby on Feb 3, 2023 [–]

I can't make sense of this.

userbinator on Feb 3, 2023 | [–]

Look for "square root by long division". That's what it seems to be called these days, but it was just taught as "the square root algorithm" when I learned it many decades ago.

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