Top blogger confesses: 'I think Grumpy's job is interesting'

From normblog:-

From the back page of the Bookseller for 10 March:

How boring is this? If you take the ISBN number of any book and multiply the first digit by 10, the second by nine, the third by eight and so on, and then add all the answers together, the total is always divisible by 11.

I didn't find it boring. I tried it with several books, and it was true for all of them. It's no accident.

Any time you'd like to hear some of my best purchase ledger anecdotes, Norm...