Number Sums

About Number Sums

Number Sums is a logic puzzle that sits at the satisfying crossroads of sudoku and arithmetic. Each grid presents rows, columns, and colored regions, and your job is to assign numbers so that every line and zone adds up to the target totals shown along the edges and within the regions. It sounds straightforward until the constraints start overlapping in unexpected ways, demanding genuine mental flexibility rather than guesswork. The puzzles scale gracefully in difficulty, making Number Sums equally rewarding for a quick mental warm-up or a deep problem-solving session that stretches your number sense.

How to Play

Select a cell and enter a number using your keyboard or the on-screen number pad. Check the row, column, and region totals against the clues displayed on the board's edges and inside colored zones. Adjust your entries until every constraint is satisfied. Use the eraser or backspace to correct mistakes without restarting.

Tips & Tricks for Number Sums

• Start with the rows or columns that have the fewest empty cells — fewer unknowns make the arithmetic constraints much easier to solve.
• Use the colored region totals as a cross-check: if your row math is right but the region sum is off, you've found exactly where the error is.
• When stuck, look for cells that sit at the intersection of two tight constraints — those cells usually have only one valid value.

Frequently Asked Questions

Game Details