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Secrets of Mental Math: The Mathemagician's Guide to Lightning Calculation and Amazing Math Tricks
by Arthur Benjamin, Michael Shermer
ISBN: 9780307338402
Found in 1 comment on Hacker News
johnisgood
· 2025-11-12 ·
Original thread
Very easy to solve, just like it is easy to solve many other ones once you know the tricks.
I recommend this book:
https://www.amazon.com/Secrets-Mental-Math-Mathemagicians-Ca...
I recommend this book: https://www.amazon.com/Secrets-Mental-Math-Mathemagicians-Ca...