A crossword made of numbers: instead of words, you fill in sums.

The rules

• Fill every white square with a number from 1 to 9.
• A run is an unbroken line of white squares, across or down. Each run must add up to its clue.
• Across clues sit in the top-right corner of the dark square to the left of a run. Down clues sit in the bottom-left corner of the dark square above it.
• No number may repeat within a run.

How to play

• Tap a square, then tap a number. The run you’re working in is shaded.
• A repeated number in a run turns orange.

Tip: some sums can only be made one way. In two squares, 3 is 1+2 and 17 is 8+9. In three squares, 6 is 1+2+3 and 24 is 7+8+9.