Xiao Ming's home is 500 meters away from the school, and there are two round trips to and from school every day. How many kilometers does she have to walk a day to go to school like this?
小明家离学校500米，每天上学回家2个来回，照这样她上学一天要走多少千米．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 / 1_000</gadget>
<output>1/250 = around 0.004</output>

<gadget id="calculator">500 * (1/250)</gadget>
<output>2</output>

<result>2</result>