An analog calculator consisting of three interlocking strips marked with logarithmic scales, such that multiplication, division etc. can be performed by the equivalent of addition and subtraction
A device, consisting of logarithmic or other scales on the outer edge of the watch face, that can be used to do mathematical calculations One of the scales is marked on a rotating bezel, which can be slid against the stationary scale to make the calculations Some watches have slide rules that allow specific calculations, such as for fuel consumption by an airplane or fuel weight
A slide rule is an instrument that you use for calculating numbers. It looks like a ruler and has a middle part that slides backwards and forwards. A device consisting of two logarithmically scaled rules mounted to slide along each other so that multiplication, division, and other more complex computations are reduced to the mechanical equivalent of addition or subtraction. an old-fashioned instrument used for calculating numbers, that looks like a ruler and has a middle part that slides across