Answer: logarithms

AnswerCrossword Clue
LOGARITHMSNumbers on slide rules
LOGARITHMSShortcuts for complex multiplication
LOGARITHMSFunctions for slide rules
logarithmsA quantity representing the power to which a fixed number (the base) must be raised to produce a given number
logarithmsLOGARITHM, a mathematical operation used esp before electronic computing, to simplify multiplication and division