title: Add each value in one column to each value in second column in Google Sheets
body: <p>Would like to have each value in one column added to each value in a second column to created a compounded array.  Was thinking I could use ARRAYFORMULA for this, but not that easy, it appears.  I want the result column automatically expanded like ARRAYFORMULA does because the number of rows can change and be unequal between Col 1 and Col 2:</p>
  
  <pre><code>Col 1 | Col 2 | Result
  ------+-------+-------
  10    |   1   | 11
  ------+-------+-------
  20    |   2   | 12
  ------+-------+-------
  30    |   3   | 13
  ------+-------+-------
  40    |       | 21
  ------+-------+-------
  50    |       | 22
  ------+-------+-------
        |       | 23
  ------+-------+-------
        |       | 31
  ------+-------+-------
        |       | 32
  ------+-------+-------
        |       | 33
  ------+-------+-------
  etc...
  </code></pre>
  
  <p>I could write a script that creates this ONEDIT() when an indicator value changes, but would prefer a formula.</p>
  
  <p>Thanks!</p>