The features of this textbook series reflect the important shift towards the 21st century competencies and a greater appreciation of mathematics, as articulated in Singapore mathematics curriculum and other international curricula. Every chapter begins with a Chapter Opener and an Introductory Problem to motivate the development of the key concepts in the topic. The Chapter Opener gives a coherent overview of the big ideas that will frame the study of the topic, while the Introductory Problem positions problem solving at the heart of learning mathematics. Two key considerations guide the development of every chapter – seeing mathematics as a tool and a discipline. Opportunities to engage in Investigation, Class Discussion, Thinking Time, Journal Writing and Performance tasks are woven throughout the textbook to enhance students' learning experiences. Stories, songs, videos, and puzzles serve to arouse interest and pique curiosity. Real-life examples serve to influence students to appreciate the beauty and usefulness of mathematics in their surroundings.