Number Nibbles: free online sudoku with a daily challenge and parties with friends

Fill every square so each row, column and 3×3 box holds the digits 1-9 exactly once. Tap a square, then a number, or tap a number first to arm it, then paint it into squares.

Pencil marks ✏️ jot small maybe-numbers in a square; placing a real digit nearby rubs matching marks out for you.

A candy shows its working: it points at the row, column or box that proves the digit, so you learn the trick.

Teacher depth 🎓 choose how much sudoku theory a candy hint may use before it simply hands you the digit.

• Just answers: no teaching, the candy quietly fills the square in
• The basics: singles, locked candidates, and pairs, triples and quads
• Clever tricks: all of the above, plus X-wings, swordfish, colouring, XY and W-wings, empty rectangles, finned X-wings and unique rectangles
• Chains: all of the above, plus jellyfish, finned big fish, X-chains, WXYZ-wings and XY-chains
• Everything: the lot, up to grouped chains and full alternating inference chains