There are 80 boxes of super soap in the store, and each box is 20 yuan. After half of the boxes are sold, how many pieces are left? (calculated in two ways)
商店有80箱超能皂，每箱20块，卖出一半后，还剩多少块？(用两种方法计算)
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">80 * 20 * (1/2)</gadget>
<output>800</output>

<result>800</result>