Sumlock Comptometer - Calculator Charts

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These calculator charts assisted users of Sumlock comptometers to perform calculations, particularly when dealing with Imperial units of measurement.  Comptometers were mechanical devices used for calculation, often powered by a hand crank.  Having tables to hand of common fractions and conversions speeded up the calculating process considerably.

Charts listed include:

  • Metric/Imperial conversion tables
  • Pence and Farthings as decimals of shillings and pounds (and several other charts involving imperial currency)
  • Common fractions and their decimal equivalents
  • Minutes as decimals of an hour


Reference Number :

Date Published : 1967

Manufacturer : Sumlock Comptometer Limited

Format : A4 Ringbound






This exhibit has a reference ID of CH43279. Please quote this reference ID in any communication with the Centre for Computing History.

Sumlock Comptometer - Calculator Charts

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