BC. Casting Out Nines
How do modern “trap-door” encryption schemes work? Over the next three weeks we'll explain, but to warm up, we talk about the medieval practice of “casting out nines”.
How do modern “trap-door” encryption schemes work? Over the next three weeks we'll explain, but to warm up, we talk about the medieval practice of “casting out nines”.
Peter Winkler answers his puzzle set in the Land of Kleptomaniacs, and we chat about Martin Gardner. We'll pose another puzzle next week!
We answer last week's puzzle and Peter Winkler asks how to send a ring through the land of the kleptomaniacs.
A common investment strategy takes advantage of the subtleties of averaging.
Is a man of perfectly average height, and perfectly average weight, too heavy for his size? Averages are not what they seem to be.
Dennis Shasha, author of The Puzzler’s Elusion explains how his finger multiplication works!
Peter Winkler answers. Another puzzle next week!
Peter Winkler, author of “Mathematical Puzzles: A Connoisseur's Collection”, asks how many coins are needed to cover a table.
Two players take turns removing coins from a line; how can the first player always be sure to have at least as much money as the second?
The solution to the balls puzzle and a quick puzzle about cards.