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