Xiaohua practiced running for 4 minutes. Each subsequent point runs the same distance less than the previous point. It is known that the first two minutes ran a total of 500 meters, and the last two minutes ran a total of 420 meters. How many meters did the last minute run?
小华练习4分钟跑．后面每分都比前一分少跑相同的距离．已知前两分共跑500米，后两分共跑420米，最后一分跑多少米？
<gadget id="calculator">500 - 420</gadget>
<output>80</output>

<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">420 - 20</gadget>
<output>400</output>

<gadget id="calculator">400 / 2</gadget>
<output>200</output>

<result>200</result>