PROJECT 4 - SUDOKU

Instructions:

You have to fill the number grid, so that every horizontal row, every vertical column and every 3 x 3 box contains digits 1 to 9, without repeating the digits in the same row, column or box.

You can’t change the numbers already given in the grid.

PROJECT 4 - SUDOKU

Procedure:

We start with the 3 x 3 grid, or row or column, already having maximum numbers.2nd row from the bottom has two missing numbers. These are 2 and 6. We write 6 in the 3rd box from left and 2 in the 8th box. We can't write 2 in the 3rd box, because2 is already written in corresponding column.

2. Next, the first column from right has two missing numbers. These numbers are 8 and9. We write 9 in the 3rd box from top and 8 in the fourth box. We cannot write 8 in place of 9, because 8 is already there in the 3 x 3 grid.

3. Next, the 2nd column from right has two missing numbers. These numbers are 1 and6. We write 1 in the 3rd box from top and 6 in the last box. We cannot write 6 in place of 1, because 6 is already there in the corresponding row.

Next, last 3 x 3 grid has only 1 number missing, which is 8.

5. Next, the first row from bottom has two missing numbers. These numbers are 1 and 9. We write 9 in the 2nd box from left and 1 in the 6th box. We can't write 1 in place of 9, because 1 is already there in the corresponding column.

6. Next, the 3 x 3 grid at left and bottom has one missing number, which is 2.

7. Next, the 3rd row from top has one missing N8 9number, which is 8.

8. Next, the top left 3 x 3 grid has one missing number, which is 6.

9. Next, the 2nd column from left has one missing number, which is 5.

10. Next, the top middle 3 x 3 grid has two missing numbers, these are 4 and 8.

We write 8 in the 4th column from left and 4 in the 5th column. We can’t interchange these numbers, because 4 and 8 are already there in the 4th and 5th column resp., from left.

11. Next the 4th column from left has one missing number, which is 5.

12. Continuing in this manner, we can fill up all the boxes as shown above.

PROJECT 4 – SUDOKU - Solution

Instructions:

You have to fill the number grid, so that every horizontal row, every vertical column and every 3 x 3 box contains digits 1 to 9, without repeating the digits in the same row, column or box.

You can’t change the numbers already given in the grid.