Résumé
Fifth and seventh graders were asked to provide a quick and rough estimate of the number of items in collections of 11—79 items. We collected verbal strategy reports and performance on each item. Results showed that: (a) participants used six different estimation strategies, (b) overall, fifth and seventh graders used the same set of strategies but varied in how often they used each strategy, (c) fifth graders’ strategy repertoire was smaller than seventh graders’, and (d) strategy selection varied as a function of children’s age, and of numerosities and configurations of items. These findings show that different processes are available for approximate quantification in both fifth and seventh graders, and document age-related differences in children’s approximate quantification.