This book reflects the modern level of the theory of problem-solving differential methods in mathematical physics. The main results of the stability and convergence of the approximate boundary problem solving for many-dimensional equations with partial derivatives are obtained in the works of Russian scientists and are practically not covered in the monograph and textbooks published in the West. At the present time the main attention in computational mathematics is paid to the theory and practice of the method of finite elements. The books available in English are oriented to the basic training of specialists. The book is intended for specialists in numerical methods for the solution of mathematical physics problems; the exposition is easily understood by senior students of universities.