Wolfgang asks how I came up with the birthday formula. While I was tempted to tell him that it was a special secret, I decided I would come clean. Here’s the formula:
A couple of years ago, a friend of mine sent me an email on my birthday. We had a long email conversation about our impending trip to the Lake of the Ozarks and there was about 20 people on the email distribution list. Some of them starting asking how old I was, and not wanting to tell them, I gave them a formula similar to the one above. Not a single one of them figured that they could put that formula into Excel to get the answer.