This is a full classroom-ready slide deck for Chapter 3 of the Cambridge IGCSE Economics course (syllabus 0455): Opportunity Cost. Designed to build genuine understanding of one of the most important and most frequently examined concepts in the course, this deck takes students from a precise definition through to confident application across four real-world decision-making contexts. Opportunity cost is a concept that appears throughout the Cambridge syllabus - getting it right at this stage matt