A water tank can hold 10 liters of water. If 500 ml of water is put in every second, how many seconds will it be full?
一个水缸可盛水10升，如果每秒放500毫升水，多少秒可以放满．
<gadget id="calculator">1_000 / 500</gadget>
<output>2</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>