If your spread sheet is missing the leading zero in the number, here is a quick way to fix it:
- Make the column (for example column B) that contains the numbers without the leading zero to be "text" or "general" format.
- Go to a cell at in the same row as the first number in the list but in an adjacent column (for example cell C2).
- In cell C2, enter this formula: =Concatenate(0,B2)
- Copy that formula down column C for the entire length of the list of number.
Column C should now contain the entire list with the leading zero added on at the beginning.
Remember: Do this step in the Excel workbook before you convert the file to CSV.