This guidance report focuses on improving the quality of teaching of mathematics to pupils in Key Stages 2 and 3. The decision to focus on these Key Stages was made after an initial consultation period with teachers, academics, and other stakeholders. Schools are seeking advice on adjusting to a new curriculum, and there is also concern about pupils making a transition between the stages. This report is not intended to provide a comprehensive guide to mathematics teaching, but rather is an accessible overview of existing research with clear, actionable guidance. Recommendations based on research findings that schools can use to make a significant difference to pupils' learning, and those based on the questions that appear to be most salient to practitioners, are provided. Those recommendations include: (1) Use assessment to build upon pupils' existing knowledge and understanding; (2) Use manipulatives and representations; (3) Teach strategies for solving problems; (4) Enable pupils to develop a rich network of mathematical knowledge; (5) Develop pupils' independence and motivation; (6) Use tasks and resources to challenge and support pupils' mathematics; (7) Use structured interventions to provide additional support; and (8) Support pupils to make a successful transition between primary and secondary school.