If a batch of goods is transported 6 times by car, if it is transported 18 times by truck. Now it is transported twice by car first, and then transported by car and cart together. How many times will it take to finish the transport?
一批货物，若用汽车运6次运完，若用大车运18次运完．现在先用汽车运2次后，再由汽车、大车合运，还需要几次才能运完？
<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">(1/6) + (1/18)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(2/3) / (2/9)</gadget>
<output>3</output>

<result>3</result>