There are 3200 chickens in the farm, which are sold in the first week (3/8) and in the second week (2/5). How many are left unsold?
养殖场有鸡3200只，第一周卖出(3/8)，第二周卖出(2/5)．还剩多少只没卖？
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (3/8) - (2/5)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">3_200 * (9/40)</gadget>
<output>720</output>

<result>720</result>