The NA() Function

• 1). Locate an empty cell on your worksheet.
  
  
• 2). Enter the following function into the empty cell:
  NA()
  Make sure to include the parentheses.
  
  
• 3). Repeat Steps 1 and 2 for each empty cell in the spreadsheet.
  
  

Checking for Bad Inputs

• 1). Locate the first function in your worksheet.
  
  
• 2). Check the inputs for the function. For example, if you have the following SUM function:
  =SUM(A1:A10)
  then check cells A1 through A10, making sure the inputs are valid.
  
  
• 3). Repeat steps 1 and 2 for all functions on your worksheet.