The number crossword game, where you fill the crossword grid with numbers based on addition logic. Anyone who can add two numbers can play.
In a language crosswords, often you are frustrated with a clue, the answer of which God only Knows. Unlike crossword, the Cross-Sum puzzles are always solveable by anyone who can add two numbers.
Cross-Sum is a nice mixture of sudoku (the japanese number puzzle game) and the Crossword (popular puzzle of western world).
The game is compact, and easily understandable. You are provided with 30 puzzles of varying sizes and difficulty levels. The game is a freeware, and if you like the game you can download more puzzle sets for free from Yoogi Games.