Doppel Sum
Shade two cells in every row and column and fill the rest with digits so each clue equals the sum between its two blocks. Live brackets fill toward the clue. Thirty puzzles from 5x5 to 7x7.
Play nowHow to play
Controls
Tap- Tap a cell, then a digit or the block button.
- Every row and column has exactly two blocks and each digit once.
- The number outside a line is the sum of the digits between its two blocks.
About the game
Doppel Sum is a number puzzle about pairs. In every row and every column exactly two cells are blocked out, and the remaining cells hold the digits from 1 up to the grid size minus two, each exactly once. The clues around the edge tell you one thing: the sum of the digits sitting between the two blocks of that line. A clue of 0 means the blocks touch; the largest possible clue means they sit at both ends.
The twist is the live bracket. As soon as a line has both of its blocks, a bar appears between them and fills toward the clue as you add digits, turning green when the sum lands and red if it overshoots. The current sum also appears next to the clue, so you can always see how much is still missing. Small grids teach the idea, and the 7x7 boards ask you to juggle several lines at once. Thirty puzzles, each with exactly one answer.
Free to play in your browser. No download, no sign-up. Works on phones, tablets and computers. Your progress is saved on this device.
