How many solutions does my Sudoku have?

There are exactly 6, 670, 903, 752, 021, 072, 936, 960 possible solutions to Sudoku (about 10^21) . That's far more than can be checked in a reasonable period of time. But as luck would have it, it's not necessary to check them all.

How do you count the number of solutions in a Sudoku?

If there are no errors and the board is full, then there is one solution. If there are no errors but the board isn't full, then pick the earliest empty cell, and sum the number of solutions for the boards which contain 1, 2, ..., 9 in that cell.

How do you know if Sudoku has multiple solutions?

A sudoku can have multiple or unique solution based on the clues and their positions in the grid. If a sudoku has less than 17 clues then it will definately have mutliple solutions. But if it has 17 or more clues it can have unique or multiple solutions based on the clues positions.

What is the 45 rule in Sudoku?

The 45 rule is a basic solving-technique in Killer Sudoku. Each house (row, column, nonet) must add to 45 (the sum of the digits 1 through 9).

How many solutions does 4x4 Sudoku have?

Your students could now be asked to find all the sixteen possible arrangements with the digits 1, 2, 3, 4 in that order across the top row. Then they should show that the top row can be rearranged in 4! = 24 different ways. Hence the total possible 4x4 Sudoku Latin squares is 16 x 24 = 384.

Sudoku Tutorial #40 A must know technique.

Is there only one solution for Sudoku?

A properly formulated Sudoku puzzle has a unique solution. One can assume that a given puzzle actually is properly formulated, and use that in the reasoning, to exclude branches that would not lead to a unique solution.

Is Sudoku good for the brain?

Sudoku keeps your brain active and reduces the risk of Alzheimer's, a most common cause of dementia that affects a person's thinking and behavioural skills. Stimulates your mind: The game works on your logical thinking process as you are absorbed in solving a puzzle and eventually improve your number skills.

What is Sudoku rule of 1?

Rule 1 - Each row must contain the numbers from 1 to 9, without repetitions. The player must focus on filling each row of the grid while ensuring there are no duplicated numbers. The placement order of the digits is irrelevant. Every puzzle, regardless of the difficulty level, begins with allocated numbers on the grid.

What is the average Sudoku time?

It is believed that the average Sudoku player spends approximately 20 minutes solving a typical Sudoku puzzle. For very hard puzzles, that number can be much higher. While the game itself can be challenging and complex, several strategies can be used successfully to find the solution.

Is 6 minutes good for Sudoku?

5 minutes is more than enough time to jump start your brain, re-evaluate your Sudoku strategy, and develop a new perspective on how to view the Sudoku grid. So “take 5” and give yourself a new chance at solving Sudoku puzzles!

Can the same number be in the same spot in Sudoku?

Sudoku puzzles cannot have the same number twice in any row, column or box (container). You can take advantage of this by using deduction to determine (1) which numbers are missing, and (2) where the missing numbers go.

What is the rule of two in Sudoku?

The game of Sudoku consists of a grid of nine rows and nine columns subdivided into nine 3x3 subgrids. It has two basic rules: Each column, each row, and each box (3x3 subgrid) must have the numbers 1 to 9. No column, row or box can have two squares with the same number.

What is the magic number in Sudoku?

Now Gary McGuire, a mathematician at University College Dublin, has come up with what he says is a proof that finds the minimum number of clues, or starting digits, needed to complete the game is 17.

Can you solve Sudoku mathematically?

In fact, mathematical thinking in the form of logical deduction is very useful in solving Sudokus. The most basic strategy to solve a Sudoku puzzle is to first write down, in each empty cell, all possible entries that will not contradict the One Rule with respect to the given cells.

Are all Sudoku solvable?

The vast majority of puzzles don't require the trickier techniques, but there are some which just aren't solvable by simple logic alone, and require various forms of guessing to solve.

What is the rule of 3 Sudoku?

If three candidates can be found in only the same three Cells of a region (Row, Column or Square), then one of these candidates is the solution for the first of these Cells, a second one is the solution for the second Cell and the last candidate is the solution for the third Cell.

What is the trick to solve Sudoku fast?

What is the fastest easy Sudoku time?

7. The Guinness World Record for the fastest solve of a 'Very Easy' level Sudoku is held by American player Thomas Snyder. He completed the puzzle in a blazing 1 minute and 23.93 seconds!

What is the 159 rule in Sudoku?

Normal sudoku rules apply: Each row, column, and region indicated by thick borders in the grid must contain the digits 1 to 9 once each. 159: Digits in column 1 indicate the column in which the digit 1 appears in that row (e.g. if r4c1 is a 6, r4c6 is a 1).

Can Sudoku have 2 answers?

A well-formed Sudoku puzzle is one that has a unique solution. A Sudoku puzzle can have more than one solution, but in this case the kind of logical reasoning we described while discussing solving strategies may fall short.

What is not allowed in Sudoku?

You can use only numbers from 1 to 9. Each 3×3 block can only contain numbers from 1 to 9. Each vertical column can only contain numbers from 1 to 9. Each horizontal row can only contain numbers from 1 to 9.

Is Sudoku high IQ?

From this case study it can be concluded that an individual who is skilled at solving Sudoku puzzles likely has a high general IQ. The results of the weak correlation between Sudoku scores and the WAIT test indicates that in some cases a high Sudoku doesn't necessarily mean a high general IQ.

Does Sudoku raise IQ?

Practising a game like sudoku or using a brain training app might make you better at it but it won't boost your IQ or general brain power, a study claims.

What kind of person is good at Sudoku?

Orderly, Methodical Mind

The best Sudoku players know how to cut through the visual clutter of a Sudoku grid and start scanning immediately for the most valuable clues and information that they need – they know how to apply a process to the Sudoku grid where they can see which places are the most promising.