This course provides introductory discussions on computational methods that aim to study and solve mathematical problems involving real variables, emphasizing the importance of studying errors. This course also discusses the mathematical foundations of numerical methods and mathematical tools, e.g., ordinary and partial differential equations, nonlinear dynamical systems, integral systems, numerical analysis, approximation theory, inverse problems and image analysis, basic theoretical properties: stability, accuracy, and computational complexity, and illustrate the method performances by means of computational examples.