In other words, if every operation takes a Modulo bitwise-and bitwise-or and bitwise-not) on variable

$online number fill in puzzles$

Only 5 operations, each of which is out of the set (addition subtraction, multiplication integer division, Combining the 8*4 bits into a 32 bits number (taking a nibble fromĮach disk), a function f from 24 bits to 32 can be computed using.Judging from the number of solvers for each, the hardest number puzzle is the one from April 2009:ĭesign a storage system that encodes 24 information bits on 8 disks of 4 bits each, such that: IBM Research has been publishing very challenging monthly puzzles since May 1998 on their

If you'd like to try it yourself, you can find it here. It appeared in the Calcudoku, 101 Advanced Puzzles book, and clearly was the least-solved puzzle, with one math professor writing that it took him 5 hours to solve, spread over multiple days. If you're not up for solving it yourself, check out thisĪ Calcudoku variation using the modulo operator Click on the puzzle to try and solve it yourself :-). Of April 2013, which only 9.6% of the regular puzzlers at Identified in the same way as the Killer Sudoku puzzle shown above, the hardest Calcudoku was a 9×9 puzzle published on the 2nd It was invented by Japanese math teacher Tetsuya Miyamoto, who called it 'Kashikoku naru' ('smartness'). To compute the result of a 'cage' (not only addition), (2) the puzzle can be any square size,Īnd (3) the Sudoku rule of requiring the numbers 1.9 in each 3×3 set of cells does not apply. Has as a solution: all patterns on the left are triangles.Ī Calcudoku is similar to a Killer Sudoku, except that (1) any operation can be used The 6 patterns on the right do not conform to this rule.įor example, the first problem on this page To solve the puzzle, you have to find a rule that the 6 patterns on the left hand sideĬonform to. They became more widely known after Douglas Hofstadter mentioned them in his bookĮasily the most information on Bongard problems

This type of puzzle first appeared in a book by Russian scientist M. (click on the puzzle to try and solve it yourself!). Easily the hardest was the Killer Sudoku published on the 9th of November 2012 shown here The original article can be downloaded here.Ī Killer Sudoku is very similar to a Sudoku, except that the clues are given as groups of cells + theĬheck out the Wikipedia page on Killer Sudoku for more information.įrom a large number of highest rated puzzles at /killersudoku, we measured what percentage of puzzlers solved them on the day The gods understand English, but will answer all questions in their own language, in which the words for yes and no are da and ja, in some order. Your task is to determine the identities of A, B, and C by asking three yes-no questions each question must be put to exactly one god. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a completely random matter. Three gods A, B, and C are called, in no particular order, True, False, and Random. Logic Puzzle Ever' :-), devised by Raymond Smullyan and published in the Harvard Review of Philosophy in 1996: That Arto's puzzle is the 3rd known hardest (although apparently the hardest puzzle listed there is in fact relativelyĪmerican philosopher and logician George Boolos described this puzzle (and called it 'The Hardest The Telegraph rated '11 out of 5 stars' :-).Īrto's web site has more information on how the puzzles are rated. In 2012, Finnish mathematician Arto Inkala claimed to have created the 'World's Hardest Sudoku', Sudoku is easily the most played and most analyzed puzzle in the world, so coming One of the World's Hardest Killer Sudokus

Online number fill in puzzles