Learn. Practise. Build real understanding.
School subjects, languages, puzzles and practical skills—with worked examples, explanations and guided practice.
27 beginner courses100 lessonsFree starter library
Sudoku by elimination
A 4×4 Sudoku uses digits 1–4 once in each row, column and 2×2 box. Start with a nearly full unit and identify the missing value. Check every placement against all three constraints.
Pencil candidates mentally or on paper, but remove candidates only when a constraint supports it. A lucky guess can appear correct briefly and still lead to a contradiction.
Worked example
A row containing 1, 2 and 4 must receive 3 in its empty square, provided column and box constraints also allow it.
Try it yourself
Play the mini Sudoku and explain one deduction before filling each square.
Check your understanding
What must every 4×4 Sudoku row contain?
Each row uses the full set exactly once.
Save this math resource for later
Save to Pinterest
Save to Pinterest