First, the intuitive method:
The intuitive method does not need any auxiliary tools, and it can solve Sudoku puzzles immediately from the moment it is received. This method mainly looks for clues and infers answers by observing the disk potential of Sudoku.
1, the only solution:
When a row, a column or a nine-square grid has eight filled numbers, the only number that can be filled in the remaining cells is the number that has not yet appeared, which becomes the only solution.
2, the basic elimination method:
Solve the problem by using the rule that the number 1 ~ 9 can only appear once in every row, every column and every nine squares. It can be divided into row exclusion, column exclusion and nine-square exclusion.
3, block exclusion method:
The row is divided into three connected small squares, and the column is also divided into three connected small squares. Jiugongge is also considered to be composed of three interconnected small squares.
Second, the candidate number method:
The candidate number rule is to establish a candidate list when solving Sudoku problem, and gradually and safely eliminate the impossible candidates of each grid candidate according to various conditions, so as to achieve the purpose of solving the problem.
1, unique candidate number method:
When the candidate number of a cell is excluded to only one number, then this number is the only candidate number of the cell, and this candidate number is the solution.
2. Implicit unique candidate number method:
When a number appears only once in the candidate number of each cell of a row, a column and nine squares, then this number is the only candidate number of this row, column and nine squares, and the value of this square can be determined as this number.
3, triple chain number deletion method:
Find out that the candidate numbers of three cells in one row, one column and nine squares do not exceed three different numbers, and then delete these three numbers from the candidate numbers in other squares. Because these three numbers can only be filled in these three cells.
Definition and benefits of Sudoku
I. Definition:
Sudoku is a kind of reasoning game, which originated in Switzerland. A digital puzzle developed in the United States and carried forward in Japan. Sudoku is nine palaces, and each palace is divided into nine squares. Give some known numbers and problem-solving conditions in this eighty-one box, and use logic and reasoning to fill in the numbers of 1-9 in other blanks.
Make every number of 1-9 appear only once in every row, column and house. This game comprehensively tests the observer's observation ability and reasoning ability. Although the game is simple, the number arrangement is ever changing. Therefore, many educators think that Sudoku is an excellent way to train the brain, not only the number changes, but also the color changes.
Second, the benefits:
1, improve mathematical thinking ability: Sudoku is a game that uses numbers to calculate and get answers, which can help players improve their mathematical thinking ability, especially their logical reasoning ability.
2, exercise thinking logic: Sudoku requires players to constantly reason and think logically according to the rules, which can help players exercise and improve their thinking logic ability.
3, improve memory: Sudoku needs to get the correct answer through the combination and arrangement of numbers, which can help players improve their memory.
4. Promote eye-hand coordination: In the process of playing Sudoku, you need to fill in the word box with your fingers quickly and accurately, which can promote the player's eye-hand coordination ability and improve the hand coordination ability.