The primary goal of this study was to assess how people process numerical ordinal information in different contexts. Specifically, we are testing the hypothesis that people tend to see some types of numbers as being ‘more ordered’ or ‘better examples’ of ordered sets than others. By varying the various rules for which sets ‘count’ as being in order (while keeping the overall types of sets people are judging constant), we can determine which types of sets match the hypothesized pattern described above. Young children struggle to see certain sets as being ‘in order’ – in particular, those sets that are not part of the count-list, like 2-4-6 or 3-6-9. We are interested in whether there are vestiges of this development challenge still present in how adults process ordered sets, in the form of subtle differences in reaction time. We hope that the results of this work will allow us to better understand the basic principles by which people represent basic numerical principles like numerical order, and how this may be linked to specific learning events that occurred early in development.