Preserve leading zeros

I have a sheet that uses an ID number of 11 digits that has 3 leading zeros.

I want to create a new ID for each entry on a new line that is identical to the first entry +1. That is easy to do but the three leading zeros disappear when I apply the formula.

The original number had to be converted to text to display the leading zeros and the formula that I use =A1+1 will not work on the text formated number. Any suggestions or help would be greatly appreciated.

Or... keep them all (original and +1s) as numbers but apply custom number format 00000000000 (eleven zeros) to the cells. This also removes the little green markers...