Ok I will try to explain this the best I can. It is really a neat thing.
Take a standard tape measure, pull out the end and bend it back toward where the tape comes out, you should have a loop, (make sure the numbers are facing each other), then put the end that you pulled out and line it up with the current year that it is. Right now you would pull it out and match the end up to 110 inches, the year representing 2010. Now look for the number on the tape measure of the year that you were born, the last two numbers of the year you were born, once you find this number look on the opposite side of the tape measure and the number you see should be your age. I hope I explained it well enough. Have fun.
Mark