TIL how to find the square root of any decimally-represented number by hand. I had never even heard of such a thing until now.
but actually...
That method didn’t quite work for me when I continued on with the sample number. I’m not sure what I’m doing incorrectly.
However, in the comments “Brian Park” explained a slightly different method which I was able to use to calculate 11 places past the decimal point.
Brian Park's comment
At 5:12 you get the 58. A much simpler way to get this is to DOUBLE the EXISTING answer gotten SO FAR. Double 29 = 58. Do the same at 6:41, doubling existing answer (29) to get 582. At 7:08, you talk about decimal point. This is much simpler if you write the answer digit over the last pair dripped down (spacing answer digits out). This way the decimal points will be vertically aligned. At 8:24 you double 2911 to get 5822. To illustrate the alignment, I show the final result calculations aligned as I suggest.
2 9 1. 1 4
4 8 47 65.23 47
4
58 4 47
4 41
582 6 65
5 81
5822 84 23
58 21
58228 26 02 47