This chapter describes the Number Navigation Game (NNG), a gamebased learning environment aimed at the promotion of fl exibility and adaptivity with arithmetical problem solving in 10- to 13-year-old students. The game design is based on an integrated approach in which the different elements of the game are directly related to the mathematical content, i.e., the use of rich networks of numerical connections in solving arithmetic problems. The interface of the game is a hundred square superimposed on various maps of land and sea, where players have to strategically navigate a ship by using different combinations of numbers and arithmetic operations. The game has two different modes encouraging the use of different arithmetic operations and number combinations. The openness of the gameplay allows players the opportunities to explore different numerical connections in an environment where there are no right or wrong answers. Future directions of the game development include additional game features and extensions to larger numbers and rational numbers.