Spinners can be used successfully for students to explore and make connections between the spinner design and the probability of an event. However, when integrated with other activities, spinners may complicate a problem situation, leading to unexpected results. In this article, we share one such experience that occurred as part of a middle grades teacher professional development project. Working with two fourth-grade teachers and their students during a lesson study involving a track meet game, we came to understand the complexities of the probability-based situation. We unveil various aspects of a problem arising from the track meet game as we review student-generated data, conduct computer simulations, seek an analytical solution to the problem, and make connections to classic problems in probability. Interactive components in the article allow for immediate computer simulation and formula evaluation.
