These lessons are designed to help you learn mathematics, think mathematically, and review what you already know. Using ideas from Building Thinking Classrooms (BTC) and the Concrete–Pictorial–Abstract (CPA) framework, the lessons move from exploring and making sense of ideas to representing them visually and finally connecting them to formal mathematical methods. Work through each lesson at your own pace, pause when you need to, revisit topics you find challenging, and use the video tutorials for additional support. Check Your Understanding questions are included throughout to help you see how well you have understood each idea. Some questions use an Open Middle-style approach, where there may be more than one way to approach a problem, encouraging you to experiment, reason, and explain rather than simply apply a memorised rule.