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.
The name derives from the Japanese word for cleverness (賢, ken, kashiko(i)).
As in sudoku, the goal of each puzzle is to fill a grid with digits –– 1 through 4 for a 4×4 grid, 1 through 5 for a 5×5, etc. –– so that no digit appears more than once in any row or any column (a Latin square). Grids range in size from 3×3 to 9×9. 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). For example, a linear three-cell cage specifying addition and a target number of 6 in a 4×4 puzzle must be satisfied with the digits 1, 2, and 3. Digits may be repeated within a cage, as long as they are not in the same row or column. No operation is relevant for a single-cell cage: placing the "target" in the cell is the only possibility (thus being a "free space"). The target number and operation appear in the upper left-hand corner of the cage.
I think I'll bag that trip for two
And pack it up to Kakadu.
Honey, it's not for the weather
Or the lack of loving you.
I got all this in between
Something I could not foresee.
All the deals I made don't matter
If I can't just let you be.
Gone again gone again
There ain't no way I'm gonna let this heart mend
Gone again
I walked in King's Cross for a while,
Gave a junkie girl a smile.
We both trade it in for danger
Or the company of strangers.
She said all her family
Was at the welfare agency,
Then she swindled my last twenty
For a kiss and some poetry.
Gone again gone again
There ain't no way I'm gonna let this heart mend
Gone again
If I don't make Kakadu,
I'll be at the Rainbow Room.
I'll be courting some disaster
With the Melbourne wrecking crew.
Honey, all this is to say
That every dog don't got its day,
If we take the love we're given
And we throw it all away.
Gone again gone again
There ain't no way I'm gonna let this heart mend