Introduction In this article we will discuss the design of the arithmetic adder and subtracter circuits. These circuits will take input bits and produce two outputs sum and carry or difference and borrow. Half adder A half adder is a logic circuit that adds two bits at a time. These two bits may be the bits of two binary numbers or a bit of one number and a carry from previous stage. This circuit take two inputs and produces two outputs a Sum and a Carry. Truth table of a half adder The Sum output has two minterms and the carry output has one minterm. So the output equation in SOP form is Boolean equation are: Sum  = A’B + AB’ Carry = AB The above equations do