Science, Technology, Engineering, and Mathematics, or STEM for short, are a group of four subject areas that are closely related to each other. Science is when you study things like nature and plants. Technology is when you use scientific knowledge to create helpful tools and machines. Engineering is when you use math and technology to design and build things like bridges and buildings. Mathematics is when you use numbers and formulas to solve problems and make calculations. STEM is important because it helps us understand the world around us and creates things that make our lives easier.