Pedagogical content knowledge was first introduced by Shulman (1986). This concept is in relation to the ability of teachers to transform the content knowledge they possess into a pedagogical form, adapted to suit the needs and abilities of the children. This study examined the ways in which primary trainees following two different routes into qualified teacher status developed confidence in mathematical pedagogical content knowledge. A case study approach was adopted focusing on trainees from a Primary SCITT (School-centred initial teacher training) and EBITT (Employment based initial teacher training) Partnership. This process explored key aspects of the training year and the perceived overall impact on the development of trainees' confidence levels in the pedagogical content knowledge aspect of mathematics. Lines of enquiry were identified related to research on the ways in which trainees learn. This included an examination of the impact of the practical experience of teaching; feedback from observations; observations of good practice; discussions with mentors and other professionals; centre-based training; discussions with peers, and previous experiences of mathematics. The trainees' perceptions of the impact of these aspects were gained through a mixed method approach and included: hard copy questionnaires, group interviews, observations of training sessions, and scrutiny of written lesson observation reports. Additional perspectives were also gained through the surveying of mentors working with the trainees and also an interview with the mathematics core tutor. Findings highlighted the importance of: reflective practice; the development of an understanding of progression in children's learning; centre-based training; the support structure within the school environment, and the teaching' experience within a second school setting. The relationship between theoretical and practical learning has been examined in detail and this highlighted the symbiotic relationship which exists between the two - concluding that both play an important role in advancing trainee teachers' confidence in mathematical pedagogical understanding.