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Sudoku
rows · columns · boxes
4×4
6×6
9×9
12×12
Fill the grid so every row, column and box contains each digit exactly once. Four grid sizes from beginner 4×4 to expert 12×12.
Easy → Devilish
4 grid sizes
Step-by-step solver
▶ Play Sudoku
➕
Calcudoku
cage arithmetic · deduce
4×4
6×6
7×7
8×8
9×9
Each cage must reach its target using the given operation. Try Operators Hidden mode — the hardest variant where you must deduce both the digits and the operation.
4 operator modes
Hidden ops
5 grid sizes
▶ Play Calcudoku
☠️
Killer Sudoku
cage sums · no operators
9×9
Standard Sudoku rules plus cage constraints — digits within each dotted cage must be unique and sum to the cage's target. No operations given.
Easy → Devilish
Unique cage digits
Solver included
▶ Play Killer Sudoku
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Number Snake
connect the numbers · find the path
5×5
6×6
7×7
8×8
9×9
10×10
Fill in the missing numbers so that 1, 2, 3 … N form a connected chain. Each number must touch the next — sides and corners both count. Also includes Orthogonal where only sides count.
Easy → Devilish
Number Snake + Orthogonal
Step-by-step solver
▶ Play Number Snake
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Futoshiki
fill the grid · satisfy the arrows
4×4
5×5
6×6
7×7
Place numbers 1–N so every row and column holds each number once. The arrows between cells tell you which neighbour is bigger — the arrow always points from the larger to the smaller number.
Easy → Devilish
Pencil notes
Step-by-step solver
▶ Play Futoshiki
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Magic Sum
fill the grid · hit every total
3×3
3×4
4×4
3×5
4×5
Place every number from 1 to N exactly once in the grid. The blue totals at the edge of each row and column are your targets — every row and column has its own individual sum to hit.
Easy → Devilish
5 grid shapes
Step-by-step solver
▶ Play Magic Sum
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Magic Difference
subtract across · hit every target
3×34×45×56×6
Subtract each row and column from its anchor cell — the result must match the edge target. Enable negative targets for extra challenge.
Easy → DevilishNegative targets optional
▶ Play Magic Difference
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Magic Product
multiply across · hit every target
3×34×45×56×6
Every row and column must multiply to the edge target. Think in factors — a completely different mental mode from addition puzzles.
Easy → DevilishFactorisation thinking
▶ Play Magic Product
÷
Magic Division
divide across · hit every target
3×34×45×56×6
Divide each row and column from its anchor cell sequentially. Enable decimal targets for harder puzzles where results aren't whole numbers.
Easy → DevilishDecimals optional
▶ Play Magic Division
±×
Magic Mixed
rows ≠ columns · 10 combos
3×34×45×5
Pick a different operation for rows and columns. Sum rows with product columns, difference rows with division columns — 10 combinations to explore.
10 op combosEasy → Devilish
▶ Play Magic Mixed
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Magic Path
connect numbers · 52 math rules
4×45×5up to 12×12
Find all numbers matching a rule — primes, multiples, Fibonacci, fractions, percentages and 46 more — then connect them in one continuous path. Drag horizontally, vertically or diagonally.
52 categories4 × 4 → 12 × 12Easy → DevilishWorks offline
▶ Play Magic Path
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Kakuro
cross-sum puzzle · fill the runs
6×6
8×8
10×10
12×12
Fill white cells with digits 1–9 so each run of cells reaches its clue total. No digit may repeat within a single run. The cross-sum classic — harder than it looks.
Easy → Devilish
Pencil notes
Step-by-step solver
▶ Play Kakuro