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Trivia Teaser

Which is the name of a substance that is at a stage between snow and ice?

Crow
Sluice
Snice
Firn

Updated daily!

Choose today's easy puzzle, or another from our extensive archive.

Difficulty Level
Top Time
Top Points
Plays

02:27
15798
23

02:26
8745
18

02:18
9409
17

02:33
9559
16

03:09
12533
20

01:36
16099
45

01:40
14949
34

01:37
14985
36

01:51
13863
35
• ## Extreme

### Yesterday's

03:45
12521
45
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To solve an Addoku, use only the numbers from 1 to 9. The numbers in squares linked by a coloured line must add up to the total given in the top left-hand corner of the set of linked squares. No individual number is repeated in any of these sets of linked squares.

Similar to Sudoku, the numbers 1 to 9 must also appear in:

• Each of the nine vertical columns
• Each of the nine horizontal row
• Each of the nine 3 x 3 boxes

Use the mouse to click up (or down) through the numbers 1 to 9 in each square. The small black arrows on each side of the square tell you whether you are counting from 1 up to 9 (right arrow) or from 9 down to 1 (left arrow).

Using your keyboard, you can type in up to eight practice numbers below the line at the top of each box.

When you have correctly completed a linked set of cells, that area fills with colour and any practice numbers will disappear.

Game Options

• YouPlay Members receive 3 save slots

PAUSE: Click to halt the timer if you wish to pause during game play

UNDO: Undo your moves one click at a time

CLEAR GRID: Undo all moves and start the Addoku again

Game Features

TOKEN COUNTER: Displays how many tokens you have won during the game

TIMER: The timer starts as soon as you open the Addoku

YouPlay BOOST: Boost your score – multiply your points by working faster and smarter

• Youplay Members receive 5 hints

Addoku is a variant of Sudoku that is sometimes called "Sum Doku" or "Killer Sudoku". Combining the logic of the traditional puzzle with unique number combinations, Addoku can often be easier to solve than Sudoku, despite its formidable name.

Unlike Sudoku, you don't begin an Addoku puzzle with any pre-determined numbers. Instead, the grid features individual cells linked by a pre-determined total. These cells must then be filled with non-duplicate numbers from 1 to 9 to match the totals and complete the puzzle.

Scientific studies have recently shown that the focused mental activity used to solve puzzles can help prevent memory loss and degenerative brain disorders such as Alzheimer's - another reason to get your daily dose of puzzling fun!

The Addoku puzzles featured on YouPlay are presented by Lovatts Publications, leaders in the industry for over 25 years. With a reputation for exceptional quality, Lovatts Addoku puzzles will provide you with hours of brain-teasing entertainment.

1. 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 made up of 1 & 2, and the total 17 can only be made up of 9 & 8. The total of 8, however, could be made up of 1 & 7, 2 & 6 or 3 & 5. It can’t be 4 & 4 because each row, column, block and set can contain the numbers 1 to 9 only once.

2. YouPlay Addoku puzzles have a space at the bottom of each cell where you can type up to eight practice numbers that could be correct.

3. Continue with the three and four-digit sets. Eventually patterns will emerge as you eliminate possibilities.

4. It is useful to remember that the numbers in each row, column and 3 x 3 block add up to a total of 45.

#### Unique Blocks

The possible numbers of most paths can be found in the following list of Unique Blocks.

 TOTAL SQUARES POSSIBLE NUMBERS CAN'T HAVE 3 2 1,2 3,4,5,6,7,8,9 4 2 1,3 2,4,5,6,7,8,9 16 2 7,9 1,2,3,4,5,6,8 17 2 8,9 1,2,3,4,5,6,7 6 3 1,2,3 4,5,6,7,8,9 7 3 1,2,4 3,5,6,7,8,9 23 3 6,8,9 1,2,3,4,5,7 24 3 7,8,9 1,2,3,4,5,6 10 4 1,2,3,4 5,6,7,8,9 11 4 1,2,3,5 4,6,7,8,9 29 4 5,7,8,9 1,2,3,4,6 30 4 6,7,8,9 1,2,3,4,5 15 5 1,2,3,4,5 6,7,8,9 16 5 1,2,3,4,6 5,7,8,9 34 5 4,6,7,8,9 1,2,3,5 35 5 5,6,7,8,9 1,2,3,4 21 6 1,2,3,4,5,6 7,8,9 22 6 1,2,3,4,5,7 6,8,9 38 6 3,5,6,7,8,9 1,2,4 39 6 4,5,6,7,8,9 1,2,3 28 7 1,2,3,4,5,6,7 8,9 29 7 1,2,3,4,5,6,8 7,9 41 7 2,4,5,6,7,8,9 1,3 42 7 3,4,5,6,7,8,9 1,2 36 8 1,2,3,4,5,6,7,8 9 37 8 1,2,3,4,5,6,7,9 8 38 8 1,2,3,4,5,6,8,9 7 39 8 1,2,3,4,5,7,8,9 6 40 8 1,2,3,4,6,7,8,9 5 41 8 1,2,3,5,6,7,8,9 4 42 8 1,2,4,5,6,7,8,9 3 43 8 1,3,4,5,6,7,8,9 2 44 8 2,3,4,5,6,7,8,9 1