How to play math crossword puzzles

Fill the nine number squares so all three equations across and all three down are true. Every number sits at a crossing, so it must work in both directions.

Place your first number

1. Choose an empty square. Its row and column are highlighted.
2. Look for an equation with just one empty square. In 3 + □ = 7, the missing number is 4.
3. Choose 4 from the tray. Check the equation that crosses that square before moving on.

The square is shared. Placing 4 makes both equations true. This small example explains a crossing; it is not a complete game board.

The number tray

Every number in the tray must be placed. A count such as ×2 means there are two tiles with that value. Given numbers, marked with a small dot, are fixed and do not use tray tiles. Erasing an entry returns it to the tray.

Read one operation at a time

Across equations read left to right. Down equations read top to bottom. Each has exactly one operation before the equals sign: a + b = c, a − b = c, or a × b = c. There is no mixed-operation precedence to guess. Every number is a positive whole number from 1 to 99; no fractions or negative answers are used.

Correct a mistake

A completed equation that does not work is marked with !. Select an entered square and replace it with a remaining tile, or choose Erase. Undo restores the previous board and hint count. Restart clears your entries after confirmation; it can also be undone.

Hint first removes one entered number that cannot match the puzzle’s unique solution. When all current entries are correct, it fills one empty square. Hint use is counted, and an undone hint is removed from that count.

Keyboard controls

• Tab reaches the board and other controls. Arrow keys move between number squares; Home and End reach the row’s ends.
• Type a digit while on an editable square to open the number field. Finish typing, then press Enter or choose Place. Escape returns to the square.
• Backspace or Delete on a square erases that entry.

Daily and practice

Sumwicker has 24 original puzzles: eight per level. Each level’s Daily puzzle changes at midnight UTC and repeats after eight days. An open daily board stays in place until you choose to open today’s puzzles. Practice chooses a different puzzle from the same eight-puzzle level.

Daily and practice progress is kept separately for each level in this browser. Storage errors are shown beside the game. A damaged saved record stays untouched unless you confirm that it should be replaced.