title: Sum data in excel only when all fields are filled
body: <p>I have a excel spreadsheet with folowing:</p>
  
  <p>Field A is manually entered and in B field I subtract 2,7% from field A. I extended that formula to all all B fields but its showing negative value as nothing is entered in all A fields.</p>
  
  <p>see screenshot:</p>
  
  <p><img src="https://i.stack.imgur.com/LrfFO.png" alt="enter image description here"></p>
  
  <p>I want only to have visible data in field B when data is entered into A field.</p>
  
  <p>How to do this?</p>
  
  <p>Thanks</p>