Book excerpt: Mastery in Primary Mathematics contains clear, practical guidance for both teachers and leaders on how to implement a mastery approach in the classroom that transcends any particular context, school type or scheme currently being used. Filled with research-based evidence, case studies and concrete examples of teaching for mastery used successfully, this is the ideal toolkit to implementing a mastery approach across a school, regardless of expertise. Moulding pupils into confident and successful mathematicians is one of the most important jobs of a primary school. It can also be one of the most difficult. Teaching for mastery gives pupils the best possible understanding of mathematics and implementing it involves a two-pronged approach: mastery must be embedded in the classroom, but will only work with the full support of the school's leadership team. Based on educational research and school case studies, Mastery in Primary Mathematics gives practical advice on introducing and sustaining teaching for mastery, with sections for both class teachers and school leaders. In this must-have guide, Tom Garry, NCETM Maths Mastery Specialist Teacher, covers the areas of variation theory, mathematical reasoning and the use of correct mathematical language, and equips leaders with the necessary tools to make the mastery approach work across a school. With a view to planning at three levels – curricular, unit and lesson – in order to fully arm educators with the means to plan effectively, Tom draws on cognitive science as current developments in this field are crucial to understanding how children learn.