found: Wikipedia, July 30, 2014(KenKen and KenDoku are trademarked names for a style of arithmetic and logic puzzle invented in 2004 by Japanese math teacher Tetsuya Miyamoto, who intended the puzzles to be an instruction-free method of training the brain. The names Calcudoku and Mathdoku are sometimes used by those who don't have the rights to use the KenKen or KenDoku trademarks. As in sudoku, the goal of each puzzle is to fill a grid with digits--1 through 4 for a 4x4 grid, 1 through 5 for a 5x5, etc.--so that no digit appears more than once in any row or any column (a Latin square). Grids range in size from 3x3 to 9x9. Additionally, KenKen grids are divided into heavily outlined groups of cells--often called "cages"--and the numbers in the cells of each cage must produce a certain "target" number when combined using a specified mathematical operation (either addition, subtraction, multiplication or division).)
found: New York times crosswords & games website, July 30, 2014(KENKEN® Puzzles)
found: KenKen puzzle official site, July 30, 2014(KenKen; math puzzles) about (it's a grid-based numerical puzzle that uses the basic math operations--addition, subtraction, multiplication, and division--while also challenging your logic and problem-solving skills. By altering the size of a KENKEN grid, from 3 x 3 up to 9 x 9, and employing different combinations of the math operations, five different difficulty levels can be generated, and a seemingly endless number of puzzles.)
