Answer: sliderule

AnswerCrossword Clue
SLIDERULEMathematical shortcut device.
SLIDERULEPocket calculator predecessor
SLIDERULEOld math calculating tool
SLIDERULEOld tool for working on logs
SLIDERULEObsolete math aid
SLIDERULECalculating device
SLIDERULECriterion for Kelly
SLIDERULELogarithmic instrument
SLIDERULEInvention of 1620
SLIDERULEManual calculator.
SLIDERULECalculating instrument.
SLIDERULECalculator.
SLIDERULETool once used with logs
SLIDERULEObsolete calculator
SLIDERULEInstrument with scales
SLIDERULECalculator ancestor
SLIDERULEObsolete math-class tool
SLIDERULEObsolete calculating tool
SLIDERULECalculator's ancestor
SLIDERULELow-tech calculator
SLIDERULEAntiquated calculator
SLIDERULEPre-calculator calculator
SLIDERULECalculator predecessor