Play Lovatts Free Daily Online Addoku (Killer Sudoku) – BETA
Killer Sudoku – the Sudoku you love, with maths! Killer Sudoku follows the logic rules of Sudoku and needs your powers of arithmetic too. It’s a perfect combination for lovers of logic.
How to solve Killer Sudoku
The Killer Sudoku / Addoku is like a traditional Sudoku in that every row, column and 3×3 block must contain the numerals 1-9. The difference is that you are not given numbers to start you off. The numbers that occur in the squares linked by a shaded line add up to the total given in the top left-hand corner of each set. No number is repeated in any of these sets. Use these totals to find the right numbers to solve the puzzle.
Use the mouse or arrow keys to select cells within the grid and then enter a number by pressing the corresponding key or using the on-screen keypad.
- Arrows : Grid movement
- Number Keys : Enter solution number
- [CTRL]+[Z] : Undo
- [CTRL]+[SHIFT]+[Z] : Redo
- [BACKSPACE] or [DEL] : Clear cell
- [SPACEBAR] : Toggle between pen and pencil mode
Killer Sudoku / Addoku tips
Single digits can be filled in straight away. Then look for two-digit sets and work out the possible combinations. For example, the total 3 can only be 1 & 2. 17 can only be 9 & 8 but 8 could be 1 & 7, 2 & 6 or 3 & 5; so it can’t be 4 & 4 because each row, column, block and set can contain only one of each number.
You can type these possible numbers in each square. Then do the same with three and four digit sets. Eventually patterns will emerge as you eliminate possibilities.
It is also useful to remember that the numbers in each row, column and 3×3 block add up to 45. If the shaded sets fill a row, column or block with just one number protruding into another row, column or block, then that number will be the total of the shaded squares minus 45.
Always remember the basic Sudoku rules that no numeral 1-9 can be repeated in any row, column, 3×3 block or set of numbers – you’ll soon unravel the Killer Sudoku!
Am I Correct?
If playing in quick mode, there is visual feedback which highlights numbers in red if they are incorrect.
The timer starts as soon as you open the Killer Sudoku. If you don’t like working against time just click on Hide Timer in the top right menu. Your time will be displayed when you finish the Addoku.
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