[M1903A1]

I have an ancient (1920-ish) American Correspondence Schools book for tradesman’s math. It’s written for about an eighth-grade level education, and is amazingly comprehensive. First math book I ever saw that showed how to crunch a square root by hand.

[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.