5 categories
Brain Games
Mind-stretching puzzles to train logic, memory, and quick thinking.
Killer Sudoku
Cage-sum Sudoku variant
Sudoku with no givens — instead, every cell belongs to a dashed cage with a target sum. Digits inside any cage are pairwise distinct.
Open generatorKakuro v2
Book-format cross sums
Cross-sums variant with mirrored header layout (sums sit on the right and bottom). Each row and column run sums to its labelled target with no repeats.
Open generatorCalcudoku v2
Book-format math grid
Larger Calcudoku puzzles with multi-cell flood-filled cages labelled in op:total form. Each row and column contains 1..N exactly once and every cage matches its target.
Open generatorMath Puzzle
Fill in the missing operand
Single-digit equations with one operand replaced by a blank. Use +, −, ×, and ÷ to figure out the missing number.
Open generatorSum Puzzle
Row and column sum targets
A small grid of digits with row and column sums printed at the edges. Fill in the hidden cells so every row and column hits its target.
Open generatorSum Search
Find numbers that add to the target
Find connected numbers in the grid that add up to the target shown in the centre. Connections can be horizontal, vertical or diagonal. Solutions included.
Open generator