<h4 style="text-align: center;"><span style="color: #666699;"><strong>Some tourists in the Museum of Natural History are looking at the dinosaur bones. </strong> <strong>One of them ask</strong><strong>s the guard, “Can you tell me how old the dinosaur bones are?” </strong> <strong> </strong><strong>The guard replies, “They are 3 million, four years, and six months old.” </strong></span><span style="color: #666699;"><strong> </strong><strong>“That s an awfully exact number,” says the tourist. “How do you know their age so precisely?”</strong></span> <span style="color: #666699;"><strong> </strong></span><span style="color: #666699;"><strong></strong><strong>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.”</strong></span></h4>
