Each level presents a square grid filled with numbers. The objective is to select or deselect these numbers so that the sum of each row and column equals the target value displayed at the edge.
By carefully evaluating which numbers to keep or remove, you gradually narrow down the correct combination.
Rullo stands out for its minimalistic design and straightforward interface. Unlike Sudoku, which uses placement rules, Rullo focuses solely on sum targets, making it easy to grasp but tough to master. It’s great for both casual play and serious logic fans who love number-based challenges.
Higher difficulty settings introduce larger grids and more complex solutions. Success relies on logical elimination, careful cross-referencing between rows and columns, and spotting patterns that help narrow down possibilities. Mistakes can be quickly undone, encouraging experimentation and learning from each attempt.
Rullo can be played for free with no downloads or sign-ups needed. It works directly in your browser, making it accessible on school and work networks for quick math challenges anytime.
The goal in Rullo is to adjust the numbers inside a grid so that the sum of each row and column matches the target values displayed at their edges.
Use your mouse to left click on numbers to include or exclude them from the sum. On mobile, simply tap numbers to toggle their active state.
As you toggle numbers, pay attention to how each change affects the totals for both rows and columns. Keep adjusting until every row and column adds up exactly to its target.
If you make a mistake, you can always click or tap again to reverse your choice. There's no time limit, so take your time to strategize your moves.
Cross-check totals - Always compare both rows and columns after each toggle. Work from the obvious - If a target matches a single number, lock it in immediately. Use process of elimination - Deselect numbers that force sums to go over the target.
Look for unique solutions - Some rows or columns will only fit one combination. Reset if stuck - Don't be afraid to clear selections and start fresh on tricky grids.
