A bag of melon seeds weighs 500 grams. After eating 20%, put the remaining 20% in. How many grams does the bag of melon seeds weigh now?
一袋瓜子重500克，吃掉20%后，再装进余下的20%，现在这袋瓜子重多少克克．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">500 * (4/5)</gadget>
<output>400</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">400 * (6/5)</gadget>
<output>480</output>

<result>480</result>