How do I explain sudoku to a child?

Every row, every column and every box must have each picture (or number) once. Find a row with only one gap first: there is only one picture it can be.

Which size should I start with?

Picture sudoku for Reception and Year 1, numbers 4×4 next, then 6×6, and 9×9 for confident older children.

Does every puzzle have one answer?

Yes. Each puzzle is checked by a solver as it is made, so there is always exactly one solution and children can reason their way to it.

Are answer keys included?

Yes, at the end of the PDF, with the missing pictures or numbers in red.

Sudoku for Kids: Picture Sudoku and 4×4, 6×6 and 9×9 Puzzles

Logic, not guessing

Sudoku has no arithmetic in it: it is pure reasoning. Children learn to look for the place with the fewest possibilities and to check every row, column and box, which is the same careful thinking good mathematicians use.

Picture sudoku first

Four pictures in a 4×4 grid is a gentle start for children who can’t yet hold numbers in their heads. They can draw the pictures or cut and glue them in.

Curriculum links in England

Maths aimsOne of the three aims of the maths curriculum is that pupils reason mathematically and explain and justify their thinking.
EYFSCreating and thinking critically, one of the characteristics of effective learning, includes developing strategies for doing things.
Managing selfThe Reception goal includes showing resilience and perseverance in the face of challenge.

Sudoku isn’t in the English curriculum, but explaining why a square can hold only one picture or number is the kind of reasoning the maths aims describe.

Ask children to say their reason aloud: “it can’t be 3, because there’s already a 3 in this row”. Many schools build that kind of explaining into maths lessons. Picture sudoku works in Reception as a small-group activity, and 9×9 puzzles suit confident pupils in Years 4 to 6, often as early-finisher work.

Summarised in our own words from the National Curriculum in England: mathematics programmes of study (aims) and the EYFS statutory framework.