Puzzles can be regarded as problem-solving games, in which players have to solve the obstacle they confront. Solving puzzles helps players to foster logical thinking and to facilitate problem-solving strategies. In this paper, we base on four puzzle games, magic square, jigsaw puzzle, sudoku, and kakuro, and then we design a number puzzle game, called number jigsaw puzzle (NJP). In solving NJP, players could construct their problem-solving strategies according to their previous knowledge. A pilot study was conducted to investigate what strategies the players would use in solving NJP. The result shows that the five different strategies had been found in the pilot study.