infix notation postfix notationreverse polish infix notation prefix notationpolish vte infix notation is the notation commonly used in arithmetical and logical formulae and statements it is characterized by the placement of operators between operandsinfixed operatorssuch as the plus sign in 2 2 usage infix notation is more difficult to parse by computers than prefix notation eg 2 2 or postfix notation eg 2 2 however many programming languages use it due to its familiarity it is more used in arithmetic eg 5 6 order of operations in infix notation unlike in prefix or postfix notations parentheses surrounding groups of operands and operators are necessary to indicate the intended order in which operations are to be performed in the absence of parentheses certain precedence rules determine the order of operations further notations infix notation may also be distinguished from function notation where the name of a function suggests a particular operation and its arguments are the operands an example of such a function notation would be s1 3 in which the function s denotes addition s1 3 1 3 4 tree traversal infix inorder is also a tree traversal order it is described in a more detailed manner on this page calculator input methods comparison of notations as used by pocket calculators postfix notation also called reverse polish notation prefix notation also called polish notation shunting yard algorithm used to convert infix notation to postfix notation or to a tree operator computer programming rpn or dal a brief analysis of reverse polish notation against direct algebraic logic infix to postfix convertor 