title: Using a function in a full cell
body: <p>The problem:</p>
  
  <p>I have a (big) column of numbers, most of which are 3-digit, some of them are 2-digit. I'd like to replace every two-digit number with first 3-digit number above.</p>
  
  <p>My question:</p>
  
  <p>Is there a way to do that? I was thinking of assigning a function to each cell in a column. This function would replace the value with a previous 3-digit if the value in cell was 2-digit, BUT do not change the value in the cell if it was 3-digit. But how do I insert a function into a full cell?</p>