The store shipped 800 plastic boxes and sold them in the morning (1/4) and in the afternoon (2/5). How many fewer were sold in the morning than in the afternoon?
商店运来800只塑料盒，上午卖出(1/4)，下午卖出(2/5)．上午比下午少卖出多少只？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(2/5) - (1/4)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">800 * (3/20)</gadget>
<output>120</output>

<result>120</result>