Design thinking is a human-centric, iterative, solution-based framework for problem solving. It involves 5 stages: empathize, define, ideate, prototype, and test. Lean focuses on learning by doing and eliminating waste through continuous improvement. Agile is an incremental and iterative methodology that embraces and adapts to change. Both agile and lean value people over process, produce iterative value, and continuously improve through reflection. The presentation discusses how design thinking, agile, and lean address the problem of complexity.