Numbers have a precision of 15 significant digits.

As it is a credit card number store it as text.

That is Format|Cell and set it to text.
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Hope this helps
Martin Fishlock
Please do not forget to rate this reply.


" wrote:

I created a spreadsheet for my personal budget. When I type a 16-digit
credit card number into a cell and then hit "enter", the last digit of
my number automatically changes to a zero. Advice??