Abstract: Simplex Method of Linear Programming is a repetitive optimizing technique to determine the possible output in order to maximize a profit in a business plan. A good foundation in Mathematics is the main tool in getting the solution. Many papers aimed to find out the Mathematics performance and the factors affecting the learner’s performance and yet this problem remained unsolved. The objective of this paper is to analyze the common errors committed by the Second Year Bachelor of Science in Accountancy students at the University of Northern Philippines. The scores of the written examination of the respondents were interpreted using error analysis. It was found out that the common errors are: basic application of the operations of numbers, determining the entering variable, miscopied values, incomplete variables in the final answer, and unfinished solution. These errors maybe due to ignorance to the rules in applying the simplex method. The study recommends giving higher percentage to basic operations in the total score of the written examination of students, Furthermore, the College should give seminars to the Accountancy students on how to manage their time in solving Mathematical problems.