## Archive for September 19, 2016

### A Week of KenKen, Day 1: Introduction

Welcome to **A Week of KenKen** (AWOKK). Every day this week, the MJ4MF blog will feature a new post about the number puzzle that Sudoku wishes it could be. That’s right — seven days, nothing but KenKen.

Here’s a list of the posts that you’ll see in coming days:

- Day 1: Intro (that’s
*today*!) - Day 2: The KENtathlon
- Day 3: KenKen Times
- Day 4: My KenKen Puzzles
- Day 5: Harold Reiter’s Puzzles
- Day 6: KenKen Glossary
- Day 7: KenKen Puzzle for 2016
- Day 8: KenKen in the Classroom

If the Beatles got nothin’ but love, babe, eight days a week, then I can certainly have a week with eight days of KenKen. Deal with it.

Today is an introduction, for those of you unfamiliar with KenKen. Here are the rules of the puzzle:

- For an
*n*×*n*grid, fill each row and column with the numbers 1 through*n*. A number may not be repeated in any row or column. - Each heavily outlined set of cells, called a
*cage*, contains a mathematical clue that consists of a number and an arithmetic operation: +, –, ×, or ÷. The numbers in that cage must combine (in any order) to produce the target number using the mathematical operation indicated. - Cages with just one cell should be filled with the target number.
- A number may be repeated within a cage, provided it’s not in the same row or column.

*The New York Times* crossword puzzle editor and *Weekend Edition* puzzlemaster Will Shortz explains KenKen in this short video:

Ready to try for yourself? Here’s a simple puzzle, which is dubbed an “easy” puzzle from the KenKen website:

Too easy? Here’s a slightly more interesting one that I created:

Did that whet your appetite for more? If you were a kid who could’ve held out for several minutes to get two marshmallows, then check back tomorrow for the next installment. But if you were a kid who just couldn’t wait and would’ve gobbled that single marshmallow immediately, then here’s your instant KenKen gratification:

- kenken.com
- Illuminations KeKen app (provided by NCTM, iPhone only)
- MathDoku Pro (my personal favorite, but Android only)

Till tomorrow, happy solving!