This is the teachers' handbook which accompanies the third year Blue Track pupils' book. It is part of a five year NMP scheme in mathematics for secondary schools and is intended to lead the student towards grades (C) D E F G in GCSE. The NMP series comprises a single textbook for all pupils in year one. In years two, three, four and five there are two tracks, Red and Blue, with a single pupil's text for each track. The Red Track leads towards the higher GCSE grades A B C (D) and the Blue Track towards the lower grades. The structure of the course aims to provide a system whereby appropriate material for the whole ability range is included in one book, and which at the same time makes allowance for pupils whose mathematical ability develops during the secondary school years. The books were written by teachers to satisfy the recommendations of the Cockcroft Report, the requirements of the GCSE National Criteria and examination syllabuses and have undergone trials in schools. They combine content and process, an important recommendation of Cockcroft and aim to promote guided active learning in order to develop pupils' skills, knowledge and understanding. This is done by the inclusion of varying sections, some of which encourage work with others, some have structured, more challenging tasks and yet others include activities, investigative work and project work. This accompanying teachers' handbook provides a concise overview of the content and aims of every chapter, reduced pages of pupils' text with page-by-page teaching notes, answers, teaching notes, details of simple equipment needed for each lesson and space for notes.