The paucity of trained and qualified teachers and poor mathematical attainment at the primary school level in Guyana triggered the introduction of the cost-effective Interactive Radio Instruction (IRI) Mathematics Programmes. This study examined teachers’ classroom practice, and explored teachers’ and pupils’ reactions to IRI in grade two mathematics classrooms. Eighteen schools, nine urban and nine rural schools, were involved in this study. Data for this study were collected via 10 focus group interviews involving 52 pupils, individual interviews with 30 teachers, and 38 classroom observations. Pupils reacted positively to the IRI radio programme, which was probably linked to their successful classroom experiences. Most of the teachers expressed reservations for the IRI methodology although it employed a wide range of teaching strategies. However, there seemed to be a lack of accountability for pupil learning. The lack of preparation and leadership by the teacher resulted in ineffective management of pupil learning. Twenty-eight per cent of the teachers observed had unsatisfactory classroom practice, and they were worst at addressing pupils’ misconceptions.