Cross Sums
Past dailiesFill every white cell with a digit from 1 to 9 so each run adds up to the clue at its start and uses no digit twice. Every puzzle has one solution you can reach by logic alone.
How to play Cross Sums
How to play
A run is a line of white cells across or down. The number above the diagonal in a green block is the sum of the run to its right; the number below it is the sum of the run beneath. Tap a cell, then tap a digit on the pad (or type it). A run may not repeat a digit.
Cross sums, also known as kakuro
This number crossword is also known as kakuro or cross additions. Some sums can be made only one way: a 2-cell run of 3 is always 1 and 2, a 3-cell run of 6 is always 1, 2 and 3, and a 2-cell run of 17 is 8 and 9.
Tips
Start where a run of few ways crosses another, and keep the digits both runs allow. Use Notes (or press N) to pencil in candidates. When only one cell of a run is empty, it is simply the clue minus the others.
Hints that teach
Hint takes one logical step, applies it to your notes or the board and explains it in a sentence, such as which digits a run can still use. Runs that go over their clue and repeated digits are marked with a stripe and a dot.
Questions
What are the rules of Cross Sums?
Write a digit from 1 to 9 in every white cell. The digits of each across or down run must add up to the clue in the block at its start, and no digit may appear twice in the same run.
Is Cross Sums the same as kakuro?
Yes. Cross Sums is the classic English name for this puzzle, which is also known as kakuro or cross additions. The rules are the same.
Does every puzzle here have exactly one solution?
Yes. Every puzzle is checked by two separate solvers that count solutions, and by a logical solver that proves it can be finished without guessing at its difficulty level.
What do the levels mean?
Small and Medium puzzles fall to run combinations and singles. Tricky and Large puzzles also need you to fit digits within a run: a cell can only take a digit if the rest of its run can still be completed.
Is there a daily Cross Sums puzzle?
Yes. The daily puzzle is a Medium 8×8 that is the same for everyone and changes at midnight UTC.