The chemical factory sells a batch of chemical fertilizers, (2/5) on the first day, and 5.2 tons on the second day, and (1/6) of this batch of fertilizers is left. How many tons are there in total for this batch of chemical fertilizers?
化工厂卖一批化肥，第一天卖出(2/5)，第二天卖出5.2吨，这时还剩这批化肥的(1/6)．这批化肥共有多少吨？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(2/5) + (1/6)</gadget>
<output>17/30 = around 0.566667</output>

<gadget id="calculator">1 - (17/30)</gadget>
<output>13/30 = around 0.433333</output>

<gadget id="calculator">5.2 / (13/30)</gadget>
<output>12</output>

<result>12</result>