My question is 2-part;

1. How do I change a column containing 4-digit numbers that were entered as
text, AND keep a zero in place if it's the first digit?

2. I'm creating what I thought was a simple spreadsheet. Nothing fancy. One
of my columns contains 16-digit numbers. I need them to display exactly as I
enter them; however, Excel has changed the last digit of every entry to "0."
I tried correcting the digits, but they still revert back to "0." How do I
get rid of that?

Many thanks!