An adding machine, a type of calculator, is specialized for bookkeeping calculations. Calculating machines in the US are built to read in dollars and cents and were commonly found in offices. However, starting around 1985, computers started to replace counting machines.
In 1623 Wilhelm Schickard built the first calculator called the “Calculating Clock”. Blaise pascal developed a similar machine in France around 1642; however, neither machine gained widespread use until Burroughs and Felt introduced them in the 1880′s.
To start adding the machine needed to be zeroed first. Next, the user pressed the numbered keys and pulled the crank. Through the use of rotary wheels the machine was able to add various calculations. However, they gained their names due to the fact that subtraction was impossible. Through the process of simply keying in the numbers one more columns to the left and repeating the addition process the machine could multiply.
The comptometer, a later version of the machine, didn’t require the crank to be pulled. The user simply pressed the keys and was thus driven by finger power rather than the crank. Some were even powered through electricity.
Now, most adding machines are like simple calculators but with a different input system.