The 9th International Conference on Numerical Methods and Applications NM&A'18 August 20 - 24, 2018, Borovets, Bulgaria is organized by Faculty of Mathematics and Informatics, Sofia University “St. Kliment Ohridski” in cooperation with Institute of Mathematics and Informatics, Bulgarian Academy of Sciences Institute of Information and Communication Technologies, Bulgarian Academy of Sciences Society for Industrial and Applied Mathematics (SIAM) Lecture Notes in Computer Science, Springer Specific topics of interest: Numerical methods for differential and integral equations Approximation techniques in numerical analysis Multi-grid, multi-level, and multi-scale methods Numerical linear algebra Reduced order models and numerical methods Hierarchical and domain decomposition methods Monte Carlo methods Orthogonal polynomials and numerical quadratures Metaheuristic algorithms and other optimization techniques Mathematical modeling in Science and Engineering Computational mechanics, physics, chemistry [...]