Interactive Mathematics Miscellany
and Puzzles

Back in 1996, Alexander Bogomolny started making the internet math-friendly by creating thousands of images, pages, and programs for this website, right up to his last update on July 6, 2018. Hours later on July 7th he passed away. His friend Nassim Taleb announced the devastating news. "He was of the few saints you meet in life: he gave more, much more than he took." Alex's family and friends have asked the Wolfram Foundation to serve as a steward for continuing maintenance and updates to the site, more details to come.

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Cut the Knot is a book of probability riddles curated to challenge the mind and expand mathematical and logical thinking skills. First housed on cut-the-knot.org, these puzzles and their solutions represent the efforts of great minds around the world. Follow along as Alexander Bogomolny presents these selected riddles by topical progression. Try them for yourself before reading their solutions. Just like it was for Alexander the Great, the non-trivial, unexpected solution might be exactly the one you need.
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This commemorative book was produced in collaboration with STEM Academic Press and Wolfram Media. Published on November 17, 2020 all proceeds from sale go to Alexander's family. For more info on the book and its release see Nassim Nicholas Taleb's post.