The computer tools for interactive mathematical activity (TIMA) were designed to provide children a medium in which they could enact the mathematical operations of unitizing, uniting, fragmenting, segmenting, partitioning, replicating, iterating and measuring. TIMA were developed in the context of a constructivist teaching experiment focused on…

In undergraduate mathematics courses, pre-service elementary school teachers are often faced with the task of re-learning some of the concepts they themselves struggled with in their own schooling. This often involves different cognitive processes and psychological issues than initial learning: pre-service teachers have had many more opportunities…