title: Difference between borrow in and borrow out?
body: <p>I was understanding the full binary subtraction logic and come across these two terms. While I understood that borrow out is the borrow you take from the next higher significant bit position ,which makes perfect sense since you can obviously take borrow from higher numbers like we use to do for decimal subtraction but <strong>B_in</strong> (borrow in ) is the borrow taken from the previous significant bit position,this is where I get confused. Formula described for such a full subtraction is :</p>
  
  <pre><code>((A - B_in) - B)
  </code></pre>
  
  <p>where A &amp; B are minuend and subtrahend respectively and B_in is the borrow taken from the previous bit position.</p>
  
  <p>So , what is this borrow in actually and how is it differentiated from borrow out ?</p>
  
  <p>Explanation with an example or two would be great. thanks.</p>