title: Calculating midpoints
body: <p>I've been unable to wrap my head around the use of <code>(low + high)/2</code> for calculating the midpoint of an array in binary search and other algorithms that use a similar operation. In my opinion it should be something like <code>low + (high-low+1)/2</code>. </p>
  
  <p>How do we arrive at former from the latter ?</p>
  
  <p>Please excuse if this is too naive. A nudge in the right direction would be greatly appreciated.</p>