title: SUM above x Cells based on value in Reference Cell
body: <p>I am currently using Google Sheets. Suppose:</p>
  
  <ul>
  <li>Cell C10 is my "Reference Cell".</li>
  <li>Cell C10 has a value of 9.</li>
  <li>Cell A10 is my "Total Cell".</li>
  </ul>
  
  <p>For Cell A10, I want to SUM the above <em>x</em> cells, based on the value in my "Reference Cell".</p>
  
  <ul>
  <li>In this example, Cell A10 would SUM the above 9 cells (since Cell C10 = 9)</li>
  </ul>
  
  <p>How can I do this?</p>