Online Sudoku for kids
Play a fresh Sudoku puzzle online with notes, hints, mistake checking and keyboard controls. Prefer paper? Print the same puzzle or the solution as a clean worksheet.
Tap a number to enter · hold one to noteTap a number to enter · Notes mode, hold, right-click or press N to note
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How to play Sudoku
Fill the 9×9 grid so that every row, every column, and each of the nine 3×3 boxes contains the numbers 1 to 9, with no repeats. Start with the rows, columns or boxes that already have the most numbers filled in.
Use notes for possible numbers, then remove candidates as each row, column and box becomes clearer. Sudoku builds logical reasoning and perseverance, no maths required, just careful thinking.
New to the game? Read the full how to play Sudoku guide, where every rule and technique is shown on a diagram.
More classroom puzzles
Looking for more printable logic activities? Try a word search, a maze or the full classroom tools.
How to solve Sudoku: strategies
Every real Sudoku has exactly one solution reachable by logic alone, no guessing needed. These are the techniques solvers reach for, roughly in the order to try them. This is the quick reference; each one is explained with a diagram in the full how-to-play guide.
1. Scanning (the starting move)
Pick a number, say 7, and scan each 3×3 box for where a 7 could legally go. Cross off any row, column or box that already has a 7. Often only one cell in a box is left, that is a placed 7. Do this for every number before moving on.
2. Obvious singles
Look at one empty cell and list every number 1 to 9 already used in its row, column and box. If only one number is left off that list, it must go in that cell, it is the only option left, plain to see.
3. Hidden singles
Sometimes a cell looks like it could hold several numbers, but one of those numbers has no other legal cell left in that row, column or box. That number is "hidden" among the possibilities, once you spot it, it can only go in that one cell.
4. Pencil marks and elimination
For a harder puzzle, lightly note every number still possible in each empty cell (pencil marks). As you fill cells in, cross candidates out of the affected row, column and box. When a cell's pencil marks shrink to one number, fill it in and repeat, the grid solves itself one elimination at a time.
5. Pairs and triples
If two cells in the same row, column or box can only be the same two numbers between them (e.g. both can only be 4 or 9), neither of those numbers can go anywhere else in that row, column or box, even though you do not yet know which cell gets which number. Cross 4 and 9 out of every other cell's pencil marks there.
Common mistake
Guessing a number because "it looks about right" instead of proving it with the rules above. A logic puzzle rewards patience, not speed, work the same box or number methodically rather than jumping around the grid.
More logic puzzles and games
Sudoku builds logical reasoning and perseverance, no maths required, just careful thinking. Looking for more? Try a word search or a maze on ChalkBee. Want to learn a different classic logic game? Our sister site Chess2ez teaches how to play chess from the very basics.