Sudoku...Numbers Game (without the math)

Sudoku ( 数独, sūdoku)
Sometimes spelled Su Doku, is a logic-based placement puzzle, also known as Number Place in the United States. The aim is to enter a numeral from 1 through 9 in each cell of a 9×9 grid made up of 3×3 subgrids (called "regions"), starting with various numerals given in some cells (the "givens"). Each row, column and region must contain only one instance of each numeral.

So for example, the 3×3 region in the top-right corner (see left) must contain a 5. By hatching across and up from 5s located elsewhere in the grid, the solver can eliminate all of the empty cells in the top-right corner which cannot contain a 5. This leaves only one possible cell (highlighted in green)--this is only one technique. The Wikipedia link on the title will tell you more. It's pretty simple and pretty addictive. No higher order math skills required.

DrPsych2b