Both Xiaohua's house and Dongdong's house are in the south of the school. Xiaohua's house is 300 meters away from the school, and Dongdong's house is 500 meters away from the school. How many meters are there between them?
小华家和冬冬家都在学校的南面，小华家离学校300米，冬冬家离学校500米，他们两家相距多少米．
<gadget id="calculator">500 - 300</gadget>
<output>200</output>

<result>200</result>