Killer Sudoku on a four by four grid. Dotted cages give you totals, and the numbers one to four fill every row, column and box.
Small enough to finish quickly, and the fastest way to learn how cages work.
Every row, column and two by two box holds one, two, three and four exactly once.
Each dotted cage shows a total. The numbers inside add up to it, and no number repeats inside a cage.
With four numbers, cages give a lot away. A two square cage totalling three has to be one and two, and a cage totalling seven has to be three and four.
Fill a square by clicking it and choosing a number. The hint button will reveal a square if you want a nudge rather than the answer.
They mark a cage. The number in its corner is the total of every square inside, and those squares all hold different numbers.
It is the best one. Every idea from the full size puzzle is here, and a four by four grid is small enough to see all of it at once.
Yes, ten. One plus two plus three plus four, in every row, column and box, which is the small grid version of the forty five rule.
Yes, at each difficulty, and you can go back to earlier days from the calendar button.
This is the miniature version of a puzzle that usually looks intimidating. Cage arithmetic on a small grid is immediately readable, and the leap to the nine by nine board gets much shorter afterwards.
The useful habit is to write out a cage's possible combinations before filling anything in. On this grid there are rarely more than two.
If you want the same grid without the sums, Sudoku 4x4 is the plain version.