A half adder is a simple logic circuit that combines two binary numbers. Logic circuits are a basic part of computers. They accept input and produce output according to mathematical logic rules.
A half adder is one of the most basic combinational logic circuits in computing. It is used to combine single-digit binary numbers. The half adder produces two numbers as output: the carry and the sum. The sum is the first digit of the answer, while the carry is any additional digit. It is called the carry because it carries over. Half adders only work with single digit inputs. When numbers containing more than one digit are to be combined together, a full adder is used.