I have a calculation that I do not even know where to begin with. It is a
check digit calculation. I can easily come up with the sum, but then the fun
begins. I need to divide the sum by 10. Seems easy enough, except that I
need to end up with a remainder, not a fraction or decimal. So if i end up
with 79, I need to end up with the 9 or eventually after subtracting the
remainder from 10, the 1. In this case the 1 is the check digit. Any ideas?