Thanks,

I think I did not explain my question well.

If I know the whole number then it is very easy.

I know only the following serial numbers:

4021246379
4021246380
4021246381
4021246382
4021246383
4021246384
4021246385

What i want to get is the following



Serial No

40212463794
40212463802
40212463810
40212463828
40212463836
40212463844
40212463851

The last digit which added with the number is a check digit and the
check digit is arrived by
=Number-10*INT(Number/10)

My problem is that the number in the above formula is the number
including the check digit.
And that check digit is unknown for me.

What I thought is that there would be a mathematical equation to find
out that part then I could put it as the last digit in my number my
number.

Thanks