Mingming and Liangliang's house are both in the east of the school. Mingming's house is 800 meters away from the school, and Liangliang's house is 1,200 meters away from the school. How many meters are there between them?
明明和亮亮家同在学校的东面，明明家离学校800米，亮亮家离学校1200米，他们两家相距多少米．
<gadget id="calculator">1_200 - 800</gadget>
<output>400</output>

<result>400</result>