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Sudokus: What Are They, and How Are They Solved?

Have you ever tried to solve a Sudoku? Sudokus are one of the most popular pastimes in the world. These puzzles require logic and problem-solving skills, so they can help you develop your maths skills. Let’s learn how to play Sudoku and some tips on how to solve them!

What Are Sudokus?

Traditionally, sudokus are number puzzles that are played on a 9×9 grid subdivided into 3×3 smaller grids. But… that is not the only type of sudoku that exists! Nowadays, we can find sudokus of different sizes and not only numerical, but also with letters or images.

For example, take a look at this 6×6 sudoku presented in the Smartick sessions with images of fruits instead of numbers:

Example of sudoku on a 6 by 6 grid to be filled in with 6 types of fruit.

How to Solve Sudokus

We have seen that sudokus are puzzles in which some pieces are placed from the beginning, and you have to place the rest respecting three rules. Let’s see them as we solve this sudoku:

Example for solving 4x4 sudokus

  • The first rule is that there cannot be any repeated objects in any column.

Try it! What to put in the coloured column – a carrot, a tomato, a cauliflower or an ear of corn?

Sudoku with the column with only one hole to fill.

Have you thought about it? What you have to put is… a tomato!

  • The second rule is that there can be no repeated objects in any row.

Try again! What to fill this row with?

Same example, in this case with a row with only one hole marked.

And now, what’s missing? Another tomato!

  • The third rule is that there can be no repeated objects in any region.

Come on! Try again! What is missing in this region?

Sudoku with a region marked with only one hole.

You’ve already learned all the basic rules for doing Sudoku! Do you remember them? I’m going to write them all together again:

  1. There can be no repeated objects in any column.
  2. There cannot be any repeated objects in any row.
  3. There cannot be any repeated objects in any region.

Now it’s your turn to finish figuring out how to fill in this Sudoku!

Sudoku of the example with the boxes to be filled in.

Strategies for Solving the Most Difficult Sudoku Puzzles

Solving some sudokus may seem difficult at first, but there are some strategies that can help you:

  1. Look for the easy holes first. Look for numbers or pictures that can only go in a certain box. That is, fill in as many boxes as you can by following the rules we just saw. For example, if there is only one empty cell in a row that can contain a certain number, then that cell must have that number.
  2. Use logic for the hard cases. Once you have completed the easier boxes, look for patterns in the grid. For example, if there are two boxes in a column that can only have two numbers, and both numbers are the same, then those numbers cannot appear in any other box in that row.
  3. Guess and check. If you get to a point where you can’t solve any more boxes using logic, guess one of the possible numbers and see if you can complete the rest of the grid. If it doesn’t work, then the guess was incorrect and you should try another possible number.

Additional Tips

Here are some more tips to help you solve sudokus that may help you solve them:

  • Practice with easier sudokus at first before attempting a more difficult one.
  • Write down the possibilities in the boxes, so you can quickly see what options may still go there.
  • Don’t give up! If you can’t solve the sudoku quickly, sometimes taking a break and trying again later can help.

In Smartick’s logic sessions, you will find a didactic sequence in which you will learn how to make sudokus, practicing from the easiest examples to others of greater difficulty. Come in, register and try our learning method for free!

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Fun is our brain’s favorite way of learning
Diane Ackerman
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