With its name derived from the Japanese word for "cleverness," KenKen is a style of arithmetic and logic puzzle invented to be an instruction-free method of training the brain.
If you're not familiar with KenKen, watch the video here and start with a 3x3 square to understand the rules. Challenge yourself with larger and larger grids. Then try creating your own unique puzzle!
Start by examining the KenKen puzzle. The puzzle is composed of a grid of squares with an equal number of columns to rows. Puzzles come in different sizes.
The goal of KenKen is to fill the puzzle with digits so that no number repeats in any row or column. Digits are determined by the puzzle size, so a three by three puzzle grid will use the digits one through three.
Look for the heavily outlined boxes inside the puzzle. These are called cages.
Fill in any cages that have only one square. The number in the upper corner is the only number that can go there.
Fill in the remaining cages by following the mathematical operation indicated in the top corner of the cage to produce the number indicated. The order in which digits in a cage are subtracted or divided does not matter.
Identify cages where only one combination of numbers will work, and fill that combination in. Digits can be repeated in a cage as long as they do not repeat in a row or column.
Experiment with different numbers in the square you're unsure of, (this is where the eraser comes in handy!)
Create your own!