Justifications-on-demand as a device to promote shifts of attention associated with relational thinking in elementary arithmetic Molina González, Marta Mason, John Forms of attention Number sentences Relational thinking Student responses to arithmetical questions that can be solved by using arithmetical structure can serve to reveal the extent and nature of relational, as opposed to computational thinking. Here, student responses to probes which require them to justify-on-demand are analysed using a conceptual framework which highlights distinctions between different forms of attention. We analyse a number of actions observed in students in terms of forms of attention and shifts between them: in the short-term (in the moment), medium-term (over several tasks), and long-term (over a year). The main factors conditioning students´ attention and its movement are identified and some didactical consequences are proposed. 2013-03-11T07:55:11Z 2013-03-11T07:55:11Z 2009 info:eu-repo/semantics/article Molina, M. y Mason, J. Justifications-on-demand as a device to promote shifts of attention associated with relational thinking in elementary arithmetic. Canadian Journal of Science, Mathematics and Technology Education, 9(4): 224-242 (2009). [http://hdl.handle.net/10481/23912] 1492-6156 1942-4051 doi: 10.1080/14926150903191885 http://hdl.handle.net/10481/23912 eng info:eu-repo/semantics/openAccess Taylor and Francis