The need for a comprehensive textbook that thoroughly addresses the topics of Basic Mathematics for Form three according to the current competence based syllabus was the driving force behind the writing of this book. This book has been prepared taking into consideration the change from content-based to competencebased curriculum and considers the social, cultural, global, technological and cross-cutting issues taking place worldwide, and particularly in Tanzania. Formerly titled, Standard Basic Mathematics, the title of this edition has been changed to reflect the many additions and improvements that have been incorporated after it was acquired by APE Network. To take into account and address the varying learning abilities of students, we have used simple language, plenty of worked examples and step by step explanations of principles and procedures. At the end of each chapter there is a section for consolidation questions as well as a topic summary. These features are meant to give the student enough practice exercises which help to consolidate the concepts that he/she has learnt in each chapter. The book has 8 chapters which covers all the competences identified in the current syllabus. It is our belief that this book will be helpful to students, teachers and other learners of mathematics, and will be an important ingredient for producing better mathematicians.