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Comment by JdeBP | Hacker News Reader

> In Devi’s case, we don’t know what techniques she used for this demonstration. Why? Because she never told people.

Yes we do. Yes she did.

Devi published a book in 1977, entitled Figuring: The Joy of Numbers. "Cubes and Cube Roots" is chapter 9.

All of the stuff that Peter S. Magnusson claims that Devi never told people about taking the cube root of an 8-digit number is right there in Devi's 1977 book, on page 81 in my copy.

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Yep, I still remember reading the book when my dad it got for me (I was 8!). I don't recall everything, but few things stuck with me from the book. Exponential growths, for example. I sort of recall that she took the example of either how does a rumor spreads, or about MLM selling cookers. Or it was the two together! (I need to check the Archive link after demonstrating that some nuggets stuck with me, and have helped made sense of stuff somehow :)

I was never good with numbers so didn't actually tried those calculations, but just reading the book was like enlightenment. (We got pleased too quickly as kids...).

Thanks for this!

Edit. My memory is very hazy! I read most of her books, these examples were in her "Puzzles to Puzzle you" and other books. Or maybe not, but here are some more: (found on a pdf... http://sriramanavidyalaya.school/assets/files/More%20Puzzles...)

Edit. Check out 66th puzzle. Not related to examples, but hey -- this is something I still use to get paid! Highly recommend this book for your young ones. :)

archive.org! My copy was on the bookshelf next to the computer. (-:

On the subject of memory: The section on pi has two mistakes, alas, which I found to be particularly unfortunate. One of the mnemonic poems has a misprint "never more" instead of "nevermore", leading to a knock-on error in the digits beneath it, and there's a second error in the digits where the word "passed" in the poem is counted incorrectly as 5 letters.

Unfortunately, that's what I first memorized pi from. I had to re-learn the correct decimal expansion.

As for the 66th puzzle, there's a clear inspiration for slipping that sort of question in and seeing if anyone who doesn't know better actually comes up with an answer. It's interesting to note that some of the items have indeed been answered since 1985. I wonder whether M. Devi had heard Robert Schuller's tale, which was in wide circulation by 1983.

* https://snopes.com/fact-check/the-unsolvable-math-problem/

Completely agree. This is the "formal training required" part that we miss while recounting these anecdotes. I still love the book, as in, It's giving you a sea to dip a little, look at pretty cool turtles, but one's gotta take a deep dive once in a while.

Thankfully I was never very good with numbers, so I only memorized it till the 6th digit so I could use it as my password!

(thankfully I can let my computer fix those for me :)

Better memory: "I used to think, hey I got sorta close to 10th digit, soon I'll know a lot more, yay!"

Ah, Edit: The deep dive should be with someone to pick you back out, in my experience.

> Figuring: The Joy of Numbers

Archive.org (link to the chapter): https://archive.org/details/B-001-014-505/page/n81/mode/2up

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