The firm of "Carlsen Brothers" from Gentoft in Denmark built two interesting and innovative lines of mechanical calculators under the "Contex" brand name.Contex Adding machine, In grey/blue/cream plastic with 48 digits and 9 results window. Comes in brown embossed vinyl wooden case with hinges, and lined with red felt. Leatherette.CONTEX Serial no. 411017021adding machines, calculators

1946 One of the first Contex calculators, the Half-Keyboard Adder used Leibniz step cylinders to perform simple addition. The predominant use of this Contex would have been adding sterling currency. Starting from the right, the levers were used for half and quarter pence, the next row would be pence, followed by shilling up to 19, and pounds. On the far left there is a zeroing lever for the entire mechanism; Ref: Online: 'physicsmuseum.uq.edu.au'Used by the office staff at the SECV construction of the Kiewa Hydro Electric Scheme.Bakelite small typing machine consisting of numbers with a screen above.'Context' embossed centre front 'Lubrication' with instructions and with Patents on bottom 'Chartres Business Service' at back 'Numbers 1 - 5' at front on knobscontex, adding machine, office equipment

An adding machine is like a calculator enabling the user to do addition and subtraction and multiplication and division by repetition. Adding machines provided a printed receipt for each entry and calculators display information on a screen.Adding machines were used in the office and were replaced by calculators and comptometers.Used by a resident of the Kiewa Valley and possibly in the SECV office.Formerly UKV 242 or Contex UKV 253 - Electric (no cord). Beige and grey plastic covered adding machine with blue numbers and black function keys. Paper roll winder and dispenser at the top of the machine. Charcoal coloured plastic base with label and patent information. A blue handle for carrying. 2 small grooved wheels on the base.Left hand front: Addmaster label and logo Base: Label on base - "Addmaster Corp. Made in USA serial number 175614". Patent information labeladding machine, addmaster, mathematics