Children are often intrigued by number patterns and games and so it makes sense for teachers to include them in their mathematics lessons. Puzzles encourage the use of critical thinking skills and provide practice in important skills areas. The use of games fosters mathematical learning and encourages the mathematical processes that children use. The Square Tool, an emerging technology using Java, was created to promote students' interest in mathematics and has the potential to greatly assist the young students in better understanding mathematics and number sense concepts. This article describes how this free Web-based tool can be used to enhance students' number sense across the primary school grades. (Contains 4 figures.)