How many Sudokus are possible?

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. Various symmetry arguments prove that many of these grids are equivalent.

How many possible Sudokus exist?

There are 6,670,903,752,021,072,936,960 possible solvable Sudoku grids that yield a unique result (that's 6 sextillion, 670 quintillion, 903 quadrillion, 752 trillion, 21 billion, 72 million, 936 thousand, 960 in case you were wondering). That's way more than the number of stars in the universe.

How many possible 9x9 Sudoku grids are there?

They discovered that the number of possible 9 by 9 Sudoku grids is N=6670903752021072936960 which is approximately 6.671×10²¹.

Do Sudokus have multiple solutions?

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. There are examples of rank-3 Sudoku puzzles with 17 givens that are well-formed.

How many 4x4 Sudoku puzzles are possible?

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.

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.

Is Sudoku always 3x3?

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 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).

What's the trick to solving Sudoku?

There are more than a few techniques to solve a Sudoku puzzle, but per Conceptis Puzzles, the easiest way to a Sudoku solution is to, “Scan rows and columns within each triple-box area, eliminating numbers or squares and finding situations where only a single number can fit into a single square.” If you're looking to ...

Is there a formula for Sudoku?

For example, in the first and fourth columns beginning from the left of the 9×9 grid, we can form the following equations: m+n=a, g+n+f=g+c. In the second and last rows beginning from the top of the 9×9 grid, the following equations can be formed: b+g+f=a+g, e+n+m=a+b+d.

Is there 16 square Sudoku?

Hexadecimal Sudokus (also known as 16x16 Sudoku) are a larger version of regular Sudoku that feature a 16 x 16 grid, and 16 hexadecimal digits. Each row, column and 4x4 block contains all the digits 0 thru F (or numbers from 1 to 16, in the decimal versions).

What is the hardest level of Sudoku?

Expert level Sudoku

This hardest Sudoku puzzle is characterized by the fact that only a few numbers are shown in the Sudoku square, which consists of 9 small squares, where the cells are located 3x3.

What is the last possible number rule in Sudoku?

Last possible number is a simple strategy that is suitable for beginners. It is based on finding the missing number. To find the missing number you should take a look at the numbers that are already exist in the 3x3 block you are interested in, and in the rows and columns connected with it.

Are Sudokus good for your 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 the minimum Sudoku problem?

The fewest clues required for a proper Sudoku is 17, but not all completed grids can be reduced to a proper 17 clue Sudoku. About 49,000 unique (non-equivalent) Sudokus with 17 clues have been found. (A proper Sudoku has only one solution).

What are the 3 rules of Sudoku?

What is the one rule in Sudoku?

Sudoku Rule № 1: Use Numbers 1-9

Within the rows and columns are 9 “squares” (made up of 3 x 3 spaces). Each row, column and square (9 spaces each) needs to be filled out with the numbers 1-9, without repeating any numbers within the row, column or square.

What is the swordfish technique in Sudoku?

A Swordfish is a 3 by 3 nine-cell pattern where a candidate is found on three different rows (or three columns) and they line up in the opposite direction. Eventually we will fix three candidates somewhere in those cells which excludes all other candidates in those units.

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!

Is there 16 * 16 Sudoku?

16 x 16 sudoku puzzles work just the same as regular 9 x 9 sudoku puzzles, but they are, well, a lot bigger! Infact whereas a normal sudoku has 81 squares in it, a 16x16 sudoku has 256 squares in it, so you get a lot more puzzle for your money.

Is Sudoku cube harder than Rubik's Cube?

Variations of the Sudoku Cube are the Sudokube and Roxdoku, as well as cubes with 4×4×4 squares instead of the normal 3×3×3. This cube is very difficult compared to other cubes because as well as requiring basic knowledge of a Rubik's cube, the player must also know basic sudoku concepts.

Is Sudoku always 9 * 9?

In classic Sudoku, the objective is to fill a 9 × 9 grid with digits so that each column, each row, and each of the nine 3 × 3 subgrids that compose the grid (also called "boxes", "blocks", or "regions") contain all of the digits from 1 to 9.

Is there 0 in Sudoku?

The cool thing about this enigma is that only two possible answers can fill each blank: zero and one—and each grid has a sole solution.