In the United States, very old adding machines were usually (always?) built to read in dollars and cents. They required the user to pull a crank to add numbers. The numbers were input by pressing keys on a large keypad: for instance, the amount $30.72 was input using keys corresponding to "$30", "70¢", and "2¢", and then pulling the crank. Subtraction was impossible, except by adding the complement of a number (for instance, subtract $2.50 by adding $9,997.50).
A later adding machine, called the Comptometer, did not require that a crank be pulled to add. Numbers were input simply by pressing keys. The machine was thus driven by finger power.
Some adding machines were electromechanical -- an old-style mechanism, but driven by electric power.
Some "ten-key" machines had input of numbers as on a modern calculator -- 30.72 was input as "3", "0", "7", "2". These machines could subtract as well as add. Some could even multiply!
These old machines could be a royal pain to maintain and often gave wrong answers. It was probably better to learn to use an abacus.
Modern adding machines are like simple calculators. They often have a different input system, though.
|To figure out this:||Type this on the adding machine:|
|2+17+5=?||2 + 17 + 5 + T|
|19-7=?||19 + 7 - T|
|38-24+10=?||38 + 24 - 10 + T|
|7×6=?||7 × 6 =|
|18/3=?||18 ÷ 3 =|
|(1.99×3)+(.79×8)+(4.29×6)=?||1.99 × 3 = + .79 × 8 = + 4.29 × 6 = + T|
William Seward Burroughs received a patent for his adding machine in 1885. The Burroughs Adding Machine Company evolved to produce electronic billing machines and mainframes, and eventually merged with Sperry to form Unisys. The grandson of the inventor of the adding machine is Beat author William S. Burroughs (best known for Naked Lunch.)
The Adding Machine is also a 1923 expressionist play by the American playwright Elmer Rice. The play dramatizes