Twenty-eight, counting the number VI, which is generally either omitted
or only partly indicated. Fix a big dial two feet or more in diameter in
some prominent part of your store, and announce that when a customer has
traded an amount equal to the total figures on the dial you will present
him with a watch. Of course, the timepiece would be a very cheap one,
but many a parent will trade with you for the sake of getting a watch
for his child.