Book excerpt: The essential subject knowledge text for primary mathematics. Secure subject knowledge and understanding is the foundation of confident, creative and effective teaching. This comprehensive text includes interactive tasks, a self assessment section to allow trainees to better understand their level of knowledge and M level extension boxes to provide further challenge in all chapters. This 7th edition is updated in line with the new National Curriculum and includes updated research summaries reflecting the latest thinking. This highly recommended text helps trainee primary teachers develop and consolidate their knowledge of mathematics.