[Lonesome in Massachussets]

Square root by hand:

https://xlinux.nist.gov/dads//HTML/squareRoot.html

I like it. I tried Newton-Raphson methods, or successive approximation, but this is a direct method.

[Rodamala]

bad link. :(

[T-Bird45]

Successive approximation was the only method I ever used but I like the direct method from your link. Of course, today the problem with successive approximation is that memorizing multiplication tables are considered “drill and kill” by the Common Core Cultists.

[Former Fetus]

Thank you! This is the way I learned it, but with the use of hand-held calculators and enough time, I managed to forget it. When my son was getting to the age when he should have learned this, I asked his math teacher who stared at me like I was crazy and told me you CANNOT do a square root by hand. Since that day it has bothered me a lot, I knew I used to do square roots by hand but I asked a number of high school and college instructors and they all acted like I was crazy. Thank you for posting this, you made my day!