7 trucks can transport 336 tons of sand and soil in 6 trips. The existing sand and soil is 560 tons. It needs to be transported in 5 trips. How many more trucks need to be added?
7辆卡车6趟可以运走336吨沙土，现有沙土560吨，要求5趟运完，需要增加多少辆同样的卡车？
<gadget id="calculator">336 / 6 / 7</gadget>
<output>8</output>

<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<gadget id="calculator">560 / 40</gadget>
<output>14</output>

<gadget id="calculator">14 - 7</gadget>
<output>7</output>

<result>7</result>