An adding machine is a mechanical or electromechanical device, resembling a typewriter, designed primarily for arithmetic, especially for accountants and bookkeepers, that uses a numerical keyboard to input numbers and prints results on paper, offering a physical record of calculations, though largely replaced by electronic calculators but still used for its specialized print-and-tabulate function.

Key Features & Function
Purpose: Specializes in adding and sometimes subtracting long columns of figures, perfect for invoices, budgets, and ledgers.

Input: Typically has a numerical keyboard (full-keyboard or ten-key) where digits are entered.

Output: Prints numbers and sums onto a paper tape or roll, creating an audit trail.

Operation: Older models were hand-cranked; later ones used electricity; modern versions are often called printing calculators.

Mechanics: Works similarly to a car's odometer, with internal wheels adding numbers as keys are pressed and a lever or crank is operated.