Engaging students in comparing and contrasting, forming conjectures, generalising and justifying is critical to develop their mathematical reasoning, but there are untapped opportunities for primary school students to improve these reasoning processes in mathematics lessons. Through a case study of one task, this paper reports on levels of justifying and the connections to other reasoning processes of comparing and contrasting, forming conjectures and generalising observed among Year 3–4 Australian and Canadian students (9–10-year olds) using the mathematical reasoning actions and levels (MRAL) framework (Authors 2017). The findings revealed that examining commonalities and differences was critical to allow Year 3–4 students to form conjectures and generalise for themselves. Justifying by examples and seeking counterexamples to evaluate the conjecture were prevalent with some students attempting to develop logical argument. The findings have implications for frameworks that assess students’ levels of justifying and for teacher actions that encourage students to communicate their reasoning through oral and non-verbal as well as written communications.

吸引学生进行比较和对比，形成猜想，进行概括和论证对于发展他们的数学推理至关重要，但是小学生还有很多未开发的机会来改进数学课程中的这些推理过程。通过一项任务的案例研究，本文报告了在3-4年级的澳大利亚和加拿大学生（9-10岁）中观察到的证明水平以及与其他推理过程进行比较和对比，形成猜想和归纳的联系。数学推理动作和水平（MRAL）框架（作者，2017年）。调查结果表明，检查共同点和差异对于让3至4年级的学生形成猜想并为自己进行概括至关重要。一些学生试图发展逻辑论证，因此，通过例子论证和寻求反例来评估这个猜想是很普遍的。研究结果对评估学生辩护水平的框架以及鼓励学生通过口头和非语言以及书面交流来传达其推理的教师行为具有启示意义。