Crossnum

About Crossnum

Crossnum describes itself as a crossword without the words. Each day brings one numbered board of interlocking equations: rows and columns of numbers joined by plus, minus, times and divide signs, each ending in a result. Some cells are blank, and your job is to fill them so every equation holds.

The rules keep the arithmetic clean. The range of allowed numbers is shown above the board (for example 1 to 32 for cells and 0 to 128 for results, depending on board size), numbers you multiply and divisors cannot exceed 12, and every step must give a whole number of zero or more, so there are no fractions or negatives. Each puzzle has one solution, reachable by deduction alone.

A new puzzle arrives every day at 2:00 AM, and difficulty follows the week: easiest on Monday and hardest on Sunday. There is a tutorial and a practice game, a light and dark theme, and the site can be installed as a web app.

It suits people who like sudoku and kakuro and want a numbers puzzle that rewards careful logic rather than speed with mental arithmetic.

How to play Crossnum

1. Check the allowed number ranges shown above the board.
2. Pick a blank cell and work out which value makes both its row and its column equation true.
3. Remember that products and divisors stay at 12 or below and no step may give a fraction or a negative.
4. Fill every blank so that all equations are correct; the puzzle has only one solution.

Tips

• Start with equations that have only one blank; they can be solved directly.
• Division and multiplication limits rule out many values quickly.
• A cell shared by a row and a column must satisfy both, so test candidates in the crossing equation.
• Play the Monday puzzle first if you are new; the week gets harder towards Sunday.

Questions