Understanding students’ conceptual development and, recognizing, anticipating, and interpreting students’ reasoning are essential when planning and teaching with tasks that are open-ended. In open-ended tasks, students have a lot of freedom to choose how to produce a solution and support their work with appropriate evidence and arguments. This video gives an opportunity to consider how a simulation can be used to collect data from a random number generator that is based on some unknown probability distribution. This video is an animated depiction of the work of two real students from a sixth grade classroom as they used the simulation tool to work with the Schoolopoly task to decide whether or not a die is fair. It will be useful to read and investigate the task itself before watching the video.