keywords: Quantum numbers, quantum theory, ground state energy, wave function
In this paper, we examine some approximation methods often applied in mathematical physics and optimization/numerical analysis. The survey classifies the types of approximation methods particularly in quantum mechanics according to the complexity of the function involved in determining the methods. The strengths and weaknesses of these methods were considered in the various areas of application, and these information, provided users the opportunity of making appropriate choice on the usage of a particular method.