DIGI book, Combinational Logic Function 9.2 A Half Adder. In the third sentence, "well need" should be "will need".

 

Perhaps the contraction we'll need was intended?
Max.

 

Verified.

http://www.allaboutcircuits.com/vol_4/chpt_9/2.html

As a first example of useful combinational logic, let's build a device that can add two binary digits together. We can quickly calculate what the answers should be:

0 + 0 = 0 0 + 1 = 1 1 + 0 = 1 1 + 1 = 102

So we well need two inputs (a and b) and two outputs. The low order output will be called Σ because it represents the sum, and the high order output will be called Cout because it represents the carry out.

Thanks for the input.

 

Or the word can be left out entirely: "So we need two inputs -- a and b -- and two outputs." The use of the "--" to set off the phrase is another option that might be used. Depends on what flows better with the overall style.