title: Google Sheet take a cell by value
body: <p>I got a problem:</p>
  <p>In cell <code>C1</code>, I fill with a formula <code>=A1+B1</code></p>
  <p>In cell <code>D1</code>, I want to extract the value of <code>C1</code></p>
  <p><em>But the catch is...</em></p>
  <p>Whenever <code>C1</code> is changing due to changes in <code>A1</code> or <code>B1</code>, <code>D1</code> needs to remains with the old value.</p>
  <p>If I do fill <code>D1</code> with <code>=C1</code>, whenever <code>C1</code> change, <code>D1</code> follows.</p>
  <p>How can I avoid <code>D1</code> to stay with old value?</p>