Computer-based learning environments are proliferating in an effort to make more resources available to more students in more timely and individualized ways without overtaxing diminishing budgets. Many computer-based learning environments are designed to facilitate meaningful interaction, however, interactivity is only one of the factors that distinguishes the medium-based learning experience from a direct learning experience. The assumption in computer-based learning environments is that the understanding gained will transfer to situations in which the knowledge will be used. A study was conducted to determine if students learning from a physical, wooden abacus would be able to perform better (faster and more accurately) than students learning from a computer- simulation of an abacus. Third graders from public schools were divided into four groups and tested on interacting with a physical abacus, interacting with a computer simulation of an abacus, watching a physical abacus, and watching a computer simulation of an abacus. After instruction and practice, students were tested on their ability to use a physical abacus. Recognition test results were the same for the two groups (physical abacus versus computer simulation). The students who learned on the wooden abacus had an advantage in time and accuracy over the students who learned from the computer simulation. When asked to extrapolate what they had learned to a more advanced domain (adding), the students who learned on the wooden abacus had a more solid foundation for this than those who learned on the computer simulation. (Contains 16 references.) (SWC)