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 kindergarten and Grade 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.

Provincial curriculum links

BC mathThe Reasoning and analyzing competency: using reasoning to explore and make connections.
ON Grade 1–8The mathematical processes, such as reasoning and proving, and social-emotional learning skills in math.

Sudoku isn’t in either curriculum, and it has no arithmetic in it. It fits the thinking side of math instead: Ontario’s mathematical processes and BC’s curricular competencies both value reasoning, checking work and sticking with a hard problem. BC also asks students to explain and justify their thinking.

Ask students to explain how they knew what went in a square: “this row already has a 3 and a 4, and the box has a 1, so it must be 2.” That talk is the reasoning both provinces look for, and it is easy to hear in a short partner conversation.

Summarized in our own words from the BC Mathematics curriculum (Curricular Competencies) and Ontario’s overview of The Ontario Curriculum, Grades 1–8: Mathematics (2020).