Cong Cong's home is 500 meters away from the school. How many kilometers does he have to walk from home to school in the morning and back home after school at noon?
聪聪家离学校500米，早晨从家到学校，中午放学回到家，一天中上放学一共要走多少千米？
<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>