www.SparkyLand.com print and play - Sudoku #1

1

2

3

 

8

 

4

 

 

4

 

6

 

 

 

 

8

 

7

8

9

 

5

 

 

 

6

2

3

4

8

9

7

 

 

 

5

 

7

2

 

1

 

9

 

8

9

1

5

6

4

 

 

 

3

4

5

 

 

 

6

7

2

6

 

8

 

 

 

9

 

9

1

2

 

 

 

3

4

8

Rules

1.  All horizontal and vertical lines must contain 1 through 9 in any order with no repeats.

2.  All cubes of nine squares must contain 1 through 9 with no repeats.

 

Sample Strategy

1.  Write the possibilities for each square in small numbers.  If there is only one possibility, fill in with a large number.

2.  Scan all vertical and horizontal lines to see if there is only 1 possibility for a number.

3.  Do the same for cubes.

4.  Once you have found an answer to one square, eliminate the possibilities for that number from the cube and both horizontal and vertical lines.  That will lead you to other answers.

5.  Use these strategies and others over and over.

6.  You should never have to guess.

 

Example

Using strategy #2, you can find the missing number in the first horizontal line.  It contains all the number from 1 through 9 except for 5, so 5 is the answer for the fifth square.

Now using strategy #4, eliminate the number 5 as a possibility from the middle of the bottom horizontal line.  The middle square on the bottom line must be a 1 since that line already contains 2,3,4,6,7,8 and 9 and we have just established that it cannot be a 5.  One is the only choice left.

 

Solution

1

2

3

4

5

6

7

8

9

7

8

6

1

2

9

4

5

3

4

5

9

7

8

3

1

2

6

2

3

4

5

6

7

8

9

1

8

9

7

2

3

1

5

6

4

5

6

1

8

9

4

2

3

7

3

4

5

6

7

8

9

1

2

9

1

8

3

4

2

6

7

5

6

7

2

9

1

5

3

4

8