Yes, it isn't ideal. What you can do is put 2 apostrophes in front of the number in xls/xlsx and save it to csv. The conversion will drop one apostrophe and wh

Yes, it isn't ideal. What you can do is put 2 apostrophes in front of the number in xls/xlsx and save it to csv. The conversion will drop one apostrophe and when you open the csv it will still have one apostrophe in front of it followed by the whole number. Then you can use a formula like =RIGHT(A1,LEN(A1)-1) to remove the leading apostrophe. The number generated by the formula appears as a proper number again and is usable in calculations.