About Crossum
Crossum is a crossword built from arithmetic. Place numbers into the grid so that every row and column equation works out — addition, subtraction and a dash of clever deduction.
Each puzzle is a tight little logic knot: the numbers you place in one equation constrain all the others. Solve your way from friendly warm-ups to grids that make you earn every cell.
How to Play
- Drag numbers into the empty cells of the grid.
- Every row and column must complete a valid equation.
- Use the results at the ends of lines to deduce placements.
- Fill the whole grid correctly to clear the stage.
Features
- Math-crossword hybrid with clean, readable boards
- Pure deduction — every puzzle has one solution
- Smooth curve from easy sums to expert grids
- Play free in your browser — coming to stores soon
