Category Archives: problems and puzzles

Lost in Translation

J. E. Littlewood told a cute story about a paper he supposedly published in the Comptes Rendus de l’Académie des sciences de Paris. The paper had three footnotes, which read, in French: I am greatly indebted to Prof. Riesz for … Continue reading

Posted in linguistics, problems and puzzles | 3 Comments

17 x 17 = $289.00

This just in from Bill Gasarch: The quest for a rectangle-free four-coloring of the 17-by-17 grid is over. If you don’t know what that’s all about, and you’d like to find out, see Bill’s blog post from 2009 or my … Continue reading

Posted in computing, mathematics, problems and puzzles | 6 Comments

Divisive diversions

The ever-puzzling Peter Winkler offered three problems in the August Communications of the ACM: Does every positive integer divide some number of the form 1{0,1}*—that is, a positive integer whose decimal representation includes no digits other than 0 and 1? … Continue reading

Posted in computing, mathematics, problems and puzzles | 3 Comments

Don’t try to read this proof!

On the subject of the Collatz conjecture (also known as the 3x+1 problem), Paul Erdos remarked: “Mathematics is not yet ready for such problems.” Shizuo Kakutani joked that the problem was a Cold War invention of the Russians meant to … Continue reading

Posted in mathematics, problems and puzzles | 4 Comments


Several weeks ago, on the morning after the first winter storm here in the Boston area, I wrote about some peculiar snow geometry on porch railings. Now, following another storm (which I wish I could believe might be the last … Continue reading

Posted in problems and puzzles, science | 4 Comments