In the process of solving fully fuzzy linear programming (FLP) problems, many methods have been investigated. To find the fuzzy optimal solution of fully FLP problems, there is a need to convert the fully FLP problems into crisp linear programming (CLP) problems. There is no method which can be used directly to find the fuzzy optimal solution of the fully FLP problems without converting it into CLP problems. In this paper we investigate fully FLP problems with equality constrains in which all the parameters and variables are positive triangular fuzzy numbers. This approach can be used directly to find the fuzzy optimal solution by the simplex method(Big-M). © 2018, Springer Nature Switzerland AG.