This study was conducted in Gauteng Province and Tshwane North District. The study explored the poor performance of learners in Mathematics in the early grades. Learners’ performance is dependent on teacher input in class. Learners’ Mathematics performance is also influenced by various aspects contributing towards development such as nutrition, parental literacy which includes teachers’ knowledge of content and language in the subject taught. The poor Mathematics performance is exacerbated by lack of visual perceptual skills as the basis for learning. This study sought to investigate whether early grade teachers met this requirement. The proposed research investigated the teaching of number sense in the early grades. The research was informed by daily experience as subject advisor. The study was informed by theories of both Vygotsky and Piaget. Teaching in the Foundation Phase is mainly through group work and play and therefore this theory is appropriate. The primary research question for this study was as follows: How do teachers experience teaching number sense in the Foundation Phase? Data were collected using semi-structured interviews and observation. Purposive sampling was used to select participants for this study. Teachers from Grades 1-3 were interviewed and it was found that many lacked content knowledge and different strategies to teach number sense. Furthermore, teachers indicated that there was minimal support from HODs and subject advisors. They agreed that they needed more capacity building workshops to strengthen their knowledge and understanding of teaching number sense. The study revealed that teachers teach Mathematics in Foundation Phase without the relevant qualification. Due to the lack of knowledge and understanding of the Foundation Phase content, strategies and methods of teaching, teachers experienced challenges mainly in teaching number sense in the early grades. / Dissertation (MEd)--University of Pretoria, 2019. / Early Childhood Education / MEd / Unrestricted