Mr. Everett's Web Page

Here's a little story that may help you understand significant digits:

Some tourists at the Museum of Natural History are marveling at the dinosaur bones.  One of them asks the guard, “Can you tell me how old these bonds are?”

The guard replies, “They’re three million, four years and six months old.”

“That’s and awfully exact number,” says the tourist.  “How do you know their age so precisely?”

The guard answers, “Well, the dinosaur bones were three million years old when I started working here, and that was four and a half years ago.”