Sudoku Numb3rs
The popular CBS TV series Numb3rs features a math professor as a crime fighter. Tomorrow night's new episode, titled "All's Fair," deals with terrorism and an FBI investigation of the murder on U.S. soil of a female Iraqi activist.
The show also includes a scene in which mathematician Charlie Eppes, his father Alan, and his friend Larry solve and discuss a sudoku puzzle. This type of puzzle typically consists of a nine-by-nine grid, with numbers occupying several of the squares. The goal is to use logic to fill in the grid with the numbers 1 through 9 so that every number occurs exactly once in each row, column, and three-by-three block. Charlie mentions that there are more than 6.7 sextillion (6.7 x 1021) possible grids, so there's no shortage of such puzzles.
Among the classroom activities developed for this particular episode of Numb3rs is an exploration of sudoku puzzles. This particular activity (March 31, 2006) asks students to analyze grids that are only four-by-four to determine how many puzzles there are. It involves taking a look at a related topic: Latin squares.
A Latin square is an n-by-n grid filled with the numbers 1 through n, such that every number occurs exactly once in each column and row.
If you're interested in a truly tough challenge, you can try the sudoku puzzle that stymied the finalists in this year's World Sudoku Championship, held early this month in Lucca, Italy. See http://www.timesonline.co.uk/article/0,,18209-2082964,00.html (The Times Online). You may need to use a little guesswork to solve it!
The winner was Jana Tylova, a 31-year-old Czech accountant.
References:
Peterson, I. 2006. By the Numb3rs. Muse 10(April):43. Available at http://www.sciencenewsforkids.org/pages/puzzlezone/muse/muse0406.asp.
______. 2006. A gathering for Gardner. Science News Online (March 25). Available at http://www.sciencenews.org/articles/20060325/mathtrek.asp.
______. 2006. Math plus crime, TV style. Science News Online (Jan. 28). Available at http://www.sciencenews.org/articles/20060128/mathtrek.asp.
______. 2005. Sudoku math. Science News Online (June 18). Available at http://www.sciencenews.org/articles/20050618/mathtrek.asp.