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Arctic Sudoku
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BasicKiller

Cage combinations

What it is

Some cage sums can only be made from one set of digits.

How to spot it

Look for small and large sums in small cages: 3 in two cells is always 1+2, 17 in two cells is always 8+9, 6 in three cells is 1+2+3 and 24 in three cells is 7+8+9. See the table of unique sums on the techniques page.

Example

12312331712128989
  • Removed / placed
The cage of 3 in r1c1–r1c2 must be 1+2, and the cage of 17 in r2c1–r3c1 must be 8+9. Write those pairs as notes.

Used from level: Extra easy (Killer Sudoku)