(1) In computer mathematics, the action specified by an operator on one or more operands. For example, in the expression A = B + 3, the process of adding B to 3 to obtain A.~(2) In programming, a defined action that can be performed by a computer system; for example, addition, comparison, branching. Note: Unlike the mathematical meaning, such an operation may not involve an operator or operands; for example, the operation Halt.~(3) The process of running a computer system in its intended environment to perform its intended functions.