Calkuro 6x6 Tough How To
To solve a calkuro puzzle:

1. Fill in the numbers without repeating a number in any row or column.
2. For a 6 x 6 puzzle use the numbers 1-6.
4. The numbers in each heavily outlined set of squares (cages) must combine to equal the number 
in the top corner using the arithmetic sign indicated.
5. Cages with just one square can be filled in straight away with the target number in the top corner.
6. A number may be repeated in a cage, but not in a row or column.