Cross Sums
Also known as Kakuro. Choose your challenge – every run must hit its target.
Beginner
Compact 4×4 grid with runs up to three cells. A first taste.
4×4 grid·~7 cells to fill~3 minutesStart BeginnerEasy
6×6 grid with runs up to four cells. A gentle introduction.
6×6 grid·~16 cells to fill~7 minutesStart EasyMedium
8×8 grid with runs up to five cells. A steady challenge.
8×8 grid·~30 cells to fill~15 minutesStart MediumHard
10×10 grid with runs up to six cells. For seasoned solvers.
10×10 grid·~50 cells to fill~30 minutesStart HardMaster Mind
A sprawling 15×15 grid with runs up to seven cells.
15×15 grid·~120 cells to fill~45 minutesStart Master Mind
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Your top Beginner to Master Mind scores will show up here.
?How to play
- 1Fill every white square with a digit from 1 to 9.
- 2The shaded squares with a diagonal line give you the targets. The number in the top-right is the total for the white squares running to the right. The number in the bottom-left is the total for the white squares running below.
- 3A digit can't appear twice in the same run, but it can show up again in a different run.
How scoring works
Every solved grid earns points, and only your best score per difficulty is kept – so a sharper, faster solve is always worth another go.
Base points & target time
| Difficulty | Base | Beat the clock |
|---|---|---|
| Beginner | 50 | under 3 min |
| Easy | 100 | under 5 min |
| Medium | 250 | under 10 min |
| Hard | 500 | under 20 min |
| Master Mind | 1000 | under 45 min |
- Time bonus.Finish under the target and you earn a point for every second to spare, up to the tier's base points again. Finishing slower simply means no bonus – your score never drops for being slow.
- Flawless bonus. Solve with no hints and no wrong runs for a flat +50.
- Hints. Each hint costs 25 points; you can use up to 3 per grid.
- Wrong runs. Each run you get wrong costs 10points – counted once per run, so re-trying the same run doesn't pile on.
Total = base + time bonus + flawless bonus − hints − wrong runs, and it never falls below zero. The same breakdown appears on screen the moment you solve.