The looking-back stage is rarely observed in students’ problem solving in spite of its recognized importance. The importance of this stage is attributed to practices of engagement with queries on verification of the obtained solution(s), comparative consideration of alternative solutions, and formulation of implications for future problem solving. We refer to such practices as looking-back practices. In the present study we explored the hypothesis that the looking-back practices can be evoked in small-group classroom discussions of controversial worked-out solutions to word problems. Such tasks are known as Who-Is-Right tasks. The data consisted of audio- and videotapes of six small groups of high-school students working on a Who-Is-Right task in the context of percentage. The data analysis, informed by a discursively-oriented perspective on problem solving, attended to strategies, dialogical moves and mathematical resources enacted by the students towards attempted agreement as to which of the solutions should be endorsed and why. The findings imply that Who-Is-Right tasks have undeniable potential for supporting collective looking-back practices. In addition, the study contributes to the literature on enactment of mathematical resources in problem-solving discourse and on patterns of students’ dialogic participation in small-group problem solving.

回望阶段尽管已被公认很重要，但在学生的问题解决中却很少见到。此阶段的重要性归因于参与对获得的解决方案进行验证的查询，对替代解决方案的比较考虑以及对未来问题解决的含义的表达的实践。我们将这种做法称为回溯做法。在本研究中，我们探索了一种假设，即可以在有争议的解决单词问题的小组课堂讨论中唤起回溯实践。此类任务称为“谁是正确的”任务。数据由六个小组的高中学生的录音带和录像带组成，他们在百分比的背景下从事“谁是谁”的任务。数据分析以对问题的解决为导向，以观点为导向，并结合了学生制定的策略，对话动作和数学资源，以期就应同意哪种解决方案以及为什么采用这些解决方案达成协议。研究结果表明，“谁是对的”任务在支持集体回溯实践方面具有不可否认的潜力。此外，