SUMS

SUMS presents itself as a mathematical logic puzzle with a touch of spatial reasoning, and its entry rule is disarmingly simple: fill each empty cell by placing the numbers one by one in order, 1 then 2 then 3, and so on. The board is not a uniform square. Black cells are out of play and a few numbers are already placed at the start. Two formats coexist, Mini at 5 × 5 and the full version at 7 × 7, numbered separately. The help panel ends with a “Next” button.

1. Choose your board from the home screen: “Play Mini SUMS” for the 5 × 5, “Play SUMS” for the 7 × 7.
2. Place the numbers one by one in ascending order starting from 1, until all empty cells are filled.
3. Rely on the “Next” indicator in the header, which constantly displays the number expected next.
4. Correct with “Undo”, start over with “Clear”, and unlock yourself with “Hint”.

Because SUMS removes half of the usual decisions: the number to place is dictated, leaving only the place to find. With black cells that cut the board and a running timer, a 5 × 5 is enough to occupy the mind.

A status line serves as a dashboard above the grid: a timer, the next number to place (“Next”), and two values displayed continuously, “Current” and “Last”. Undo and Clear are grayed out, while Hint is available from the start. Performance is shown off the board: the site publishes “Today's High Scores” and personal statistics.

Mini SUMS

The 5 × 5 format, numbered separately.

SUMS

The full 7 × 7 format, with its own daily numbering.

• The order of the numbers is fixed and displayed: the question is never which number to place, but where to place it. All the difficulty shifts to placement.
• The numbers already placed at the start and the black cells segment the board: they are the only footholds before the first move.