Killer sudoku
Normal sudoku rules, plus the numbers in each dashed cage add up to its total, with no repeats inside a cage. New to killer? Start easy
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How killer sudoku works
Every row, column and 3 by 3 box still needs the numbers 1 to 9 once each. On top of that, the grid is split into cages drawn with dashed lines. The small number in the corner of a cage is what its digits add up to, and a digit cannot repeat inside a cage.
Start with the cages that only have one way to make their total. A two-cell cage of 3 must be 1 and 2. A two-cell cage of 17 must be 8 and 9. Then use the rule of 45: every row, column and box adds up to 45, so if the cages inside a box add up to 40 and one cell is left over, that cell is 5.
Cage totals with only one combination
Learn these and you will always have somewhere to start.
| Cells | Total | Must be |
|---|---|---|
| 2 | 3 | 1 2 |
| 2 | 4 | 1 3 |
| 2 | 16 | 7 9 |
| 2 | 17 | 8 9 |
| 3 | 6 | 1 2 3 |
| 3 | 7 | 1 2 4 |
| 3 | 23 | 6 8 9 |
| 3 | 24 | 7 8 9 |
| 4 | 10 | 1 2 3 4 |
| 4 | 11 | 1 2 3 5 |
| 4 | 29 | 5 7 8 9 |
| 4 | 30 | 6 7 8 9 |
| 5 | 15 | 1 2 3 4 5 |
| 5 | 16 | 1 2 3 4 6 |
| 5 | 34 | 4 6 7 8 9 |
| 5 | 35 | 5 6 7 8 9 |
Every combination for two and three cells
| 2 cells | Combinations |
|---|---|
| 3 | 1+2 |
| 4 | 1+3 |
| 5 | 1+4, 2+3 |
| 6 | 1+5, 2+4 |
| 7 | 1+6, 2+5, 3+4 |
| 8 | 1+7, 2+6, 3+5 |
| 9 | 1+8, 2+7, 3+6, 4+5 |
| 10 | 1+9, 2+8, 3+7, 4+6 |
| 11 | 2+9, 3+8, 4+7, 5+6 |
| 12 | 3+9, 4+8, 5+7 |
| 13 | 4+9, 5+8, 6+7 |
| 14 | 5+9, 6+8 |
| 15 | 6+9, 7+8 |
| 16 | 7+9 |
| 17 | 8+9 |
| 3 cells | Combinations |
|---|---|
| 6 | 1+2+3 |
| 7 | 1+2+4 |
| 8 | 1+2+5, 1+3+4 |
| 9 | 1+2+6, 1+3+5, 2+3+4 |
| 10 | 1+2+7, 1+3+6, 1+4+5, 2+3+5 |
| 11 | 1+2+8, 1+3+7, 1+4+6, 2+3+6, 2+4+5 |
| 12 | 1+2+9, 1+3+8, 1+4+7, 1+5+6, 2+3+7, 2+4+6, 3+4+5 |
| 13 | 1+3+9, 1+4+8, 1+5+7, 2+3+8, 2+4+7, 2+5+6, 3+4+6 |
| 14 | 1+4+9, 1+5+8, 1+6+7, 2+3+9, 2+4+8, 2+5+7, 3+4+7, 3+5+6 |
| 15 | 1+5+9, 1+6+8, 2+4+9, 2+5+8, 2+6+7, 3+4+8, 3+5+7, 4+5+6 |
| 16 | 1+6+9, 1+7+8, 2+5+9, 2+6+8, 3+4+9, 3+5+8, 3+6+7, 4+5+7 |
| 17 | 1+7+9, 2+6+9, 2+7+8, 3+5+9, 3+6+8, 4+5+8, 4+6+7 |
| 18 | 1+8+9, 2+7+9, 3+6+9, 3+7+8, 4+5+9, 4+6+8, 5+6+7 |
| 19 | 2+8+9, 3+7+9, 4+6+9, 4+7+8, 5+6+8 |
| 20 | 3+8+9, 4+7+9, 5+6+9, 5+7+8 |
| 21 | 4+8+9, 5+7+9, 6+7+8 |
| 22 | 5+8+9, 6+7+9 |
| 23 | 6+8+9 |
| 24 | 7+8+9 |