Teach IB Computer Science A1.3.5 with a complete 59-slide deck on multitasking, resource allocation, contention, and deadlock. Covers operating-system roles, task scheduling, context switching, single-core and multi-core execution, resource management, contention, deadlock, performance trade-offs, IB command terms, scenario analysis, retrieval practice, exam-style questions, lesson activities, common student errors, curriculum links, and HL extension topics. Includes clear explanations, diagrams, worked scenarios, teacher notes, and classroom activities. Suitable for IB Diploma Computer Science HL, first assessment 2027.