Excel only has 15 digit precision. That is why when entering a 16 digit
credit card number, you would format it as text.

"Mike One" wrote:

Format a cell as number and set decimal places to 0.

Then enter 1818181818181818 in a cell and hit enter...

Excel then CHANGES to the number to:

1818181818181810 ???? WHAT ???

This can't be right can it ??, what am I missing ?