## Rules and execise of Sudoku

Sudoku has more rules than other puzzles, but popular from beginners to experts.

## Rules of Sudoku

- Place a number (1-9) in each blank cell.
- Each row (nine lines from left to right), column (also nine lines from top to bottom) and 3x3 block bounded by bold line (nine blocks) contains number from 1 through 9.

Sample

Solution

## Sudoku exercise

Check where numbers can go to get started, so first look at the rows and columns.

For the top 3x3 blocks there is a **1** in the middle and right blocks, so there is only one place where the **1** can go in left block.

In this figure there is also only one place where the **1** can go.

Did you follow so far? The trick is to look everywhere in the Sudoku square and you will simply find where a number has to go.

Each row and block has to contain the numbers **1** to **9**.

Here is a little tip for advanced folks. Can you see where the **1** can go here?

There are two cells that may get a **1** in the top left 3x3 block, both in the same row!

So, in this figure, you can't put the **1** into the yellow cells.

Here **1** has to go in right next to the **6**. We still don't know which of the two orange cells will get the **1**, but we can specify the top middle cell where **1** has to go into.

There are many more tips. Good luck finding your own as you go along.