A car team transports a batch of cement from the factory to the construction site. On the first day, (1/4) and 7 tons of all the cement are transported, and on the second day, the remaining (2/5) and 2 tons are transported. The cement (5/18) has not been shipped, how many tons of cement are there?
一个汽车队把一批水泥从工厂运到工地，第一天运了所有水泥的(1/4)又7吨，第二天运余下的(2/5)又2吨，这样还剩下全部水泥的(5/18)没有运完，问原来有多少吨水泥？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">7 * (2/5)</gadget>
<output>14/5 = around 2.8</output>

<gadget id="calculator">2 - (14/5)</gadget>
<output>-4/5 = around -0.8</output>

<gadget id="calculator">7 + (-4/5)</gadget>
<output>31/5 = around 6.2</output>

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

<gadget id="calculator">(1/4) * (2/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">5 / 18</gadget>
<output>5/18 = around 0.277778</output>

<gadget id="calculator">1 - (1/4) - (2/5) - (5/18)</gadget>
<output>13/180 = around 0.072222</output>

<gadget id="calculator">(1/10) + (13/180)</gadget>
<output>31/180 = around 0.172222</output>

<gadget id="calculator">(31/5) / (31/180)</gadget>
<output>36</output>

<result>36</result>