If you've got the time, we've got the riddle. And it's time for a riddle about time: How many numbers are on a clock? It begins with the simplest of questions that, nevertheless, has no simple answer.

You look at your clock. And there it is, the same number. Again. What's going on? Statisticians will ask you how many times per day do you look for the time? What percentage of those times do you hit ...