Intuitionistic fuzzy sets (IFS) are more applicable and reliable to deal with the real life situations under uncertain environment. The extension principle is a vital concept in fuzzy field specially in fuzzy arithmetic. In this article, a pair of extension principles namely minimal extension principle and average extension principle are proposed for IFS with some associated properties. Moreover, some properties of general extension principle for IFSs are explored. Finally, arithmetic operations for IFSs based on the average extension principle are developed with examples.
M. K. Hasan (Thu,) studied this question.