Large numbers of primary preservice student teachers' experience maths-anxiety and negative beliefs when entering teacher education courses. This study investigated the reduction of maths-anxiety in sixteen self-identified maths-anxious preservice student teachers. These students were engaged in the development of their mathematical repertoires within the context of a supportive computer-supported collaborative learning (CSCL) environment. The design of the Intervention Program used in the study was informed by a theoretical framework derived from the literature in the fields of learning environments, novel open-ended mathematical activities, computer supported collaborative learning, community of learners and negative beliefs about learning and teaching mathematics. A focus for this study will be findings from the online anxiety survey that allowed participants to self-monitor their feelings as they engaged with the various mathematical activities. The findings suggest that a significant decrease in participant maths-anxiety occurred as they became aware of their emotional state and feelings in relation to each mathematical activity.