ANGELIC SUDOKU

Probably, in some Japanese schools, Sudoku puzzles are taught in math and logic classes. A cute little girl-angel (because of her, we called this flash game Angel Sudoku) next to the blackboard on the screen saver shows just such a learning process. And what, a good thing! Sudoku is a powerful puzzle that is extremely useful in the learning process.

To solve the puzzle, the player must fill all the empty cells with numbers so that no number is repeated within the same row, column or small square. That is, in each row, column, and small square (3x3), the numbers must be unique: from 1 to 9. Note that at the start, some numbers are already placed in the cells. It is necessary to link the rest to them, since they are a priori correct.

This version of Sudoku is good because each digit has its own unique color, so it's faster to find the missing ones. Shall we begin? Do you see the buttons in the lower-right corner? The lower one starts the game.