Numerical simulation is a method used to model complex systems by using mathematical equations and algorithms. It allows scientists and engineers to predict how these systems behave under different conditions without needing to conduct physical experiments. For example, climate scientists use numerical simulations to forecast weather patterns and understand climate change. In industries like aerospace and automotive, numerical simulations help design safer and more efficient vehicles. By simulating airflow over an aircraft or the impact of a crash, engineers can make informed decisions and improve their designs. This approach saves time and resources while enhancing innovation and safety.