In this paper, the aim is to find the nearest trapezoidal fuzzy number to a given fuzzy number which preserves the convex combination of support and core intervals of that fuzzy number. This allows the decision maker to select the preferred approximation of a fuzzy number from a class of trapezoidal approximations. Nowadays, the fuzzy concepts are widely used in many real-world engineering applications, such as population models, control chaotic systems, economics and finance, artificial intelligence, computer science, expert systems, management science, operations research, pattern recognition, robotics and others. Because of the existence of fuzzy parameters, computational complexity is the cost of fuzzy system and this matter has captured the attention of researchers for introducing methods and decreasing this cost. In general, most of the fuzzy-based algorithms use a defuzzification process that maps a fuzzy parameter into a crisp one. Obviously, in most cases, too much important information is lost by converting fuzzy sets into a set of real numbers. It seems that we should accept some criteria and apply a framework for constructing a defuzzyfication process. Van Leekwijck et al. in [21] presented a set of criteria for defuzzification strategies and classified the most widely used defuzzification techniques into different groups and they examined the prototypes of each group with respect to the defuzzification criteria.