title: Excel spreadsheet: how to find the difference between two sets of columns in the same row
body: <p>Not sure this is even possible, but perhaps someone knows how to do it. I have a row with 6 columns (A-F). The first three columns are one set and the last three columns are a different set. I want to sum both sets and then find the difference between the sums. For example if the row is:</p>
  
  <pre><code>A1 A2 A3 A4 A5 A6
  4  5  6  7  8  9
  </code></pre>
  
  <p>I want to add 4+5+6 and 7+8+9 and then find the difference between the two sums.</p>