SumRace blog

Guides, strategy and the maths behind the puzzles.

• Kakuro strategy: five techniques that solve most grids — From magic number combinations to cross-referencing runs — the core moves every Kakuro solver uses.
• Futoshiki for beginners: read the inequalities first — Why the < and > signs are the puzzle, not the grid — and how chains of inequalities hand you free digits.
• How to actually get faster at mental arithmetic — Speed comes from fewer steps, not faster steps. Three habits that cut solving time on any timed puzzle.