Cars A and B start opposite each other from places A and B at the same time, and the two cars meet each other in 4.5 hours. It is known that car A travels 45 kilometers per hour, and car B travels 55 kilometers per hour. How many kilometers are there between A and B?
甲、乙两车同时从A、B两地相对出发，4.5小时两车相遇．已知甲车每小时行45千米，乙车每小时行55千米，A、B两地相距多少千米？
<gadget id="calculator">45 + 55</gadget>
<output>100</output>

<gadget id="calculator">100 * 4.5</gadget>
<output>450</output>

<result>450</result>