Fill every white square with a digit from 1 to 9. Each dark square holds a clue. The number above the diagonal is the total of the white squares running right of it. The number below the diagonal is the total of the squares running down from it.
A digit can't repeat within a single run. Every puzzle here has exactly one solution, so you never need to guess.
Same grid, same rules, but each clue is what the digits multiply to. A clue of 24 over two squares can only be 3 and 8, or 4 and 6. Look for clues with a 5 or 7 as a factor; those digits are forced.
Tap a square, then tap a digit. Tap the same digit again to clear it.
Notes switches the keypad to pencil marks, so you can jot candidates in a square.
Check marks the selected square if it's wrong. More lets you check the whole grid, reveal a square or reset.
Using Check or Reveal still counts the solve, but it isn't marked as a clean solve in your stats. Your fastest time per puzzle is kept either way.
Two squares: 3 is always 1+2, 4 is 1+3, 16 is 7+9, 17 is 8+9. Three squares: 6 is 1+2+3, 7 is 1+2+4, 23 is 6+8+9, 24 is 7+8+9. Four squares: 10 is 1+2+3+4, 30 is 6+7+8+9.
Turn on Show combinations in Settings to see every possible digit set for the square you've selected.
A new one every day, getting harder through the week: easy early in the week and an expert grid on Sunday.