think! Mathematics is a series of textbooks designed to provide students valuable learning experiences and a deeper appreciation of mathematics by engaging their minds and hearts. The series covers the MOE Syllabus for Mathematics implemented from 2020, and reflects the important shifts towards the development of 21st century competencies. Underpinning the writing of this textbook is our belief that all students can learn and appreciate mathematics. This textbook series will be a meaningful companion for students as they embark on an exciting journey in secondary school mathematics through collaborative and self-directed learning. Special features Chapter Opener and Introductory Problem motivate the development of concepts Investigation, Class Discussion, Thinking time, Journal Writing and Performance Task highlight mathematics as a tool and as a discipline Real-life examples, applications and Problems in Real-World Contexts emphasise the relevance and beauty of mathematics Worked Examples, Practise Now and Exercise questions ensure a high baseline of mastery Challenge Yourself problems provide extension opportunities Reflection prompts encourage metacognition ICT tools