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Cross SumsShare your score
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How to play
- Pick a cell, then write a digit from 1 to 9 in it.
- Every run must total the clue written against it.
- No digit may appear twice inside the same run.
- A wrong run is washed orange and marked in the corner.
- Solve the board before the clock runs out.
Controls
Keyboard
- ← ↑ → ↓ move
- 1–9 write a digit
- 0 or Backspace clears
- Space pencil, Z undo
- H hint, M swap board, P pause
Touch
- Tap a cell, then tap a digit on the keypad below the grid
- Tap the same cell again to clear it
Controller
- D-pad or left stick to move
- A / Cross for action, B / Circle for secondary
- Start to pause
Tips for a better score
- Start where the clues are extreme: two cells adding to three must be one and two. Then follow the crossings, since each digit has to suit both its runs.
- The ladder runs 5 by 5 up to 9 by 9: bigger outlines, more cells to fill, more crossings to work with and more time on the clock.
- Space turns on pencil marks, so a digit you type becomes a small grey candidate instead; Z takes back the last change and H buys one correct cell.
- Scoring: five points each time a run first adds up, ten a cell for solving, fifty per size step above the smallest, two a second left, forty off a hint.
About Cross Sums
Cross Sums is a number crossword. The grid is split between charcoal clue cells and cream open ones, and every straight run of open cells, across or down, has to add up to the clue written against it, using the digits one to nine with no digit repeated inside that run. Boards are built in your browser as you play: a symmetrical pattern, a backtracking fill, then an exact solver that counts the answers and throws away anything with more than one, so every board you are shown has exactly one solution. There is today's board, the same for everyone until midnight and worth a hundred extra the first time you solve it, and an endless ladder that climbs from a 5 by 5 outline to 9 by 9.
A free cross sums puzzle that runs in your browser. Category: Puzzle games. Made for RetroWorld with original art and sound.
