The commonest operation of all figure work is the performance of adding function. The machine, which facilitates addition quickly, is called an adding machine. There are two types of adding machines called listing adding machine and non- listing adding machine.
Non-listing machine — The results of addition appears on, a meter and here no printing is done; In this machine necessary figures are pressed on the keyboard and the successive total is reflected on the meter without printing.
Listing machine —under this machine, the grand total of all entries is printed on a sheet of paper after the recording of all entries are over. Thus it gives a printed record of the items and its total. There are two types of listing machines called pull-key board type and Ten-key board type.