Preservice mathematics teachers are subject to multiple influences when they make in-the-moment instructional decisions in classroom settings. Little is known about which influences make a significant contribution to decisions regarding the mathematical content knowledge (MCK) that preservice teachers decide to enact. The process by which mathematics preservice teachers manage multiple influences when making those decisions also requires particular examination. This study investigated six secondary mathematics preservice teachers’ content-related decisions and actions in ten lower secondary algebra lessons using a combination of lesson observations and stimulated recall interviews. The study uncovered five influences, each comprising a number of influencing elements, that led the preservice teachers to intentionally enact or alternatively to intentionally withhold certain aspects of their MCK during algebra lessons. Combinations of harmonious influences were regularly accommodated by preservice teachers, while other combinations of influences competed for the preservice teachers’ attention at different points in their lesson. The findings reveal that simply possessing content knowledge does not mean that preservice teachers are prepared to impart that knowledge to their students in the classroom context. The multi-faceted nature of content-related decision-making for preservice teachers suggests that content knowledge development should not be attended to in isolation within teacher education programs but should be located in teaching contexts wherever possible.

职前数学教师在课堂环境中进行即时教学决策时会受到多种影响。鲜为人知的是，哪些影响因素对职前教师决定制定的数学内容知识（MCK）的决定做出了重大贡献。职前数学教师在做出这些决定时如何管理多种影响的过程也需要进行特殊检查。这项研究结合了课程观察和刺激的回忆式访谈，调查了十个初中代数课程中六个中学数学职前教师与内容相关的决策和行动。这项研究发现了五种影响，每种影响都包含许多影响因素，这导致了职前教师在代数课上有意制定或有选择地隐瞒其MCK的某些方面。职前教师会定期安排和谐影响的组合，而其他影响组合则会在课中不同点上争夺职前教师的注意力。研究结果表明，仅仅拥有内容知识并不意味着职前教师已经准备好在课堂环境中将其知识传授给学生。职前教师与内容有关的决策的多面性表明，不应在教师教育计划内孤立地关注内容知识的发展，而应尽可能地将其置于教学环境中。