Bone Up

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

The guard replies, “They’re 65,000,011 years old.”

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

“Well,” the guard answers, “they were 65 million years old when I started working here, and that was 11 years ago.”