The introduction of negative numbers should mean that mathematics can be twice as much fun, but unfortunately they are a source of confusion for many students. Difficulties occur in moving from intuitive understandings to formal mathematical representations of operations with negative and positive integers. This paper describes a series of activities that were used with a group of 14 middle school students. The approach taken attempted to bridge the gap between students' intuitions, existing mathematical knowledge and recent experience, and the mathematical concepts of operations on negative and positive integers. (Contains 6 figures.)