The supermarket brings in 2 tons of soybean oil, sells it in the first week (2/5), sells it in the second week (1/3), and sells it all in the third week. What fraction of the soybean oil sold in the third week accounted for the total number of shipments?
超市运进2吨大豆油，第一周卖出(2/5)，第二周卖出(1/3)，第三周全部卖完．第三周卖出的大豆油占运进总数的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (2/5) - (1/3)</gadget>
<output>4/15 = around 0.266667</output>

<result>4/15 = around 0.266667</result>