A cup is filled with half a cup of water, even the cup weighs a total of 400 grams. How much does the cup weigh if filled with water?
一个杯子里装了半杯水，连杯称一共400克．如果装满水，连杯称有多重？
<gadget id="calculator">400 * 2</gadget>
<output>800</output>

<result>800</result>