adder; adding machine
Refers to a device that performs addition, either a mechanical adding machine or an electronic adder circuit.
This adder can perform binary addition.
Old offices used to have adding machines.
計算機 is a general term for a calculator or computing machine, while 加算器 specifically refers to a device that adds.
Standard kanji spelling for an electronic adder or adding machine.
Alternate kanji spelling, less common than 加算器.
Compound of 加算 (addition) and 器 (device). The alternate form 加算機 uses 機 (machine) instead.