Kakuro (Cross Sums)

Think of a crossword where every answer is a sum. Cross Sums, also known as Kakuro, asks you to make each white run add up to the number in the clue square beside it, without repeating a digit.

How to play Cross Sums

• Every white square takes one digit from 1 to 9.
• The number in the upper right of a dark square is the total of the run of white squares to its right. The number in the lower left is the total of the run below it.
• A digit may not appear twice in the same run.
• Select a square to see every set of digits that can make its across and down totals in the helper below the grid.
• Each puzzle is built by our generator and verified to have exactly one solution.

Controls

• Arrow keys: move   1–9: enter   Shift + 1–9: note
• N: notes mode   Backspace: erase   Z: undo   H: hint

Tips

• Learn the totals with only one combination: 3 in two squares is 1+2, 4 is 1+3, 16 is 7+9 and 17 is 8+9.
• Where an across run and a down run cross, the digit must belong to a combination of both — compare the two lists in the helper.
• Small totals push digits low and big totals push them high; start where the clues are most extreme.

FAQ

Can a digit repeat in a row of the grid?

Yes, as long as the copies sit in different runs. Only squares in the same unbroken run must all differ.

Is Cross Sums the same as Kakuro?

Yes. Kakuro is another common name for this puzzle; the rules are identical: runs of distinct digits 1–9 that add up to their clues.

Do I need maths skills?

Only simple addition. The challenge is logic: narrowing down which combinations fit where runs cross.