The distance between A and B is 1000 meters. A and B start from A and B at the same time, and walk back and forth between A and B. If the distance between the two places A and B is 100 meters when they meet for the first time, how far is the place where the two meet for the second time from the place where they met for the first time?
A，B两地相距1000米，甲、乙二人分别从A，B两地同时出发，在A，B两地间往返散步．如果两人第一次相遇时距A，B两地的中点100米，那么，两人第二次相遇地点距第一次相遇地点多远？
<gadget id="calculator">1_000 / 2</gadget>
<output>500</output>

<gadget id="calculator">500 - 100</gadget>
<output>400</output>

<gadget id="calculator">400 * 3</gadget>
<output>1_200</output>

<gadget id="calculator">1_200 - 1_000</gadget>
<output>200</output>

<gadget id="calculator">1_000 - 200 - 400</gadget>
<output>400</output>

<result>400</result>