freexsums.com provides free Cross Sums puzzles. These puzzles, also known as Crossums, Sum Totals and Kakuro, are entertaining and educational. Enjoy a new puzzle every day.
an informational site about two of the famous puzzle games: kakuro and sudoku, with their history, play and techniques and the mathematics of both puzzle games kakuro and sudoku.
Какуро - головоломка с числами, которую можно назвать математическим аналогом кроссворда. Название Какуро происходит от японского сокращения kasan kurosu в С