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Le Monde puzzle [#1000…1025]

March 28, 2017

Le Monde mathematical puzzle launched a competition to celebrate its 1000th puzzle! A fairly long-term competition as it runs over the 25 coming puzzles (and hence weeks). Starting with puzzle #1001. Here is the 1000th puzzle, not part of the competition: Alice & Bob spend five (identical) vouchers in five different shops, each time buying […]

Le Monde puzzle [#1001]

March 27, 2017

After a long lag (due to my missing the free copies distributed at Paris-Dauphine!), here is a Sudoku-like Le Monde mathematical puzzle: A grid of size (n,n) holds integer values such that any entry larger than 1 is the sum of one term in the same column and one term in the same row. What […]

un peu de douceur dans un monde de brutes…

March 19, 2017

Le Monde puzzle [#990]

January 12, 2017

To celebrate the new year (assuming it is worth celebrating!), Le Monde mathematical puzzle came up with the following: Two sequences (x¹,x²,…) and (y¹,y²,…) are defined as follows: the current value of x is either the previous value or twice the previous value, while the current value of y is the sum of the values […]

Le Monde puzzle [#940]

November 11, 2016

A sudoku-like Le Monde mathematical puzzle: On a 3×3 grid, all integers from 1 to 9 are present. Considering all differences between adjacent entries, the value of the grid is the minimum difference. What is the maximum possible value? In a completely uninspired approach considering random permutations on {1,..,9}, the grid value can be computed […]