Two cars leave from places A and B at the same time and drive toward each other. After 4.5 hours, they meet at a distance of 9 kilometers from the midpoint. The express train travels 100 kilometers per hour. How many kilometers are there between places A and B?
两车从甲乙两地同时开出，相向而行，4.5小时后在距中点9千米相遇，快车每小时行100千米，甲乙两地相距多少千米？
<gadget id="calculator">100 * 4.5</gadget>
<output>450</output>

<gadget id="calculator">450 - 9</gadget>
<output>441</output>

<gadget id="calculator">441 * 2</gadget>
<output>882</output>

<result>882</result>