An empty cup weighs 120 grams. After filling half a cup of soybeans, the total weight of the cup is 320 grams. If a cup of soybeans is filled, how many grams does the soybean weigh?
一个空杯重120克，装半杯黄豆后，连杯共重320克，装满一杯黄豆，黄豆重多少克克．
<gadget id="calculator">320 - 120</gadget>
<output>200</output>

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

<result>400</result>