Brain Puzzles · Logic

Sudoku

Each row, column and box holds every number once. Print a fresh sheet with its answer key, or try one on screen.

🖨 Print a sheet▶ Try one on screen

How to play

  1. A 4 × 4 grid uses 1 to 4, a 6 × 6 grid uses 1 to 6, and a 9 × 9 grid uses 1 to 9.
  2. Look for a square where only one number can go, or a number that has only one place left in a row, column or box.
  3. Never guess. Every puzzle here has exactly one answer, so there is always a next step you can be sure of.

What it exercises

Careful, step-by-step reasoning. You keep several rules in mind at once and only write what you can prove.

Levels

  • Easy Many clues, solvable by spotting singles.
  • Medium Fewer clues, still no guessing needed.
  • Hard Only the clues needed for one answer.

🖨 Print a sheet

▶ Try one on screen

More logic puzzles

Cage SquaresA number grid with sums and products in outlined cages. Logic GridsUse the clues to match each child to their things. Picture LogicNumber clues tell you which squares to fill. A picture or a pattern appears. Letter ArithmeticAn addition sum in letters. Which digit is each letter? Classic BrainteasersBridges at night, water jugs, river crossings and fake coins. All Brain PuzzlesEvery kind, and the mixed sampler.
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