This article describes a recent and successful initiative on teaching place value and the decomposition method of subtraction to pupils having difficulty with this technique in the 9-12-year age range. The aim of the research was to explore whether using the metaphor of selling chews (i.e., sweets) in a tuck shop and developing this into an iconic representation of the process of decomposition could help to support children's understanding of decomposition and thus make the technique more accessible. The authors, who tried using Java applets and the EIS (enactive, iconic, and symbolic) approach in creating the "Tuckshop" project, have been very encouraged by the results. The authors cite several reasons why the project was successful: (1) The underlying metaphor of "unpacking chews" is easy to grasp; (2) Learners develop the concepts in ways that are consistent with, and build upon, their common sense; (3) The "EIS" approach draws in all types of learners, whether their preferred learning style is kinaesthetic, visual or abstract. (Contains 9 figures and 1 footnote.)