There are schools, bookstores, and supermarkets on a straight road. Now Xiaoming is in the middle of the school and the supermarket, and Xiaoli is in the middle of the bookstore and the supermarket. It is known that the distance between the school and the bookstore is 600 meters, and the distance between the bookstore and the supermarket is 400 meters. Then Xiaoming How many meters is the distance from Xiaoli?
在一条笔直的马路上有学校、书店、超市，现在小明在学校和超市正中间，小丽在书店和超市的正中间，已知学校和书店相距600米，书店和超市相距400米，则小明和小丽相距多少米？
<gadget id="calculator">600 - 400</gadget>
<output>200</output>

<gadget id="calculator">200 / 2</gadget>
<output>100</output>

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

<gadget id="calculator">100 + 200</gadget>
<output>300</output>

<result>300</result>