It takes 7 people 11 days to build a section of road; according to this calculation, if it is to be completed 4 days ahead of schedule, how many people should be added.
修一段公路，7人11天可以完成；照这样计算，如果要提前4天完成，应增加多少人．
<gadget id="calculator">11 - 4</gadget>
<output>7</output>

<gadget id="calculator">11 / 7</gadget>
<output>11/7 = around 1.571429</output>

<gadget id="calculator">7 * (11/7)</gadget>
<output>11</output>

<gadget id="calculator">11 - 7</gadget>
<output>4</output>

<result>4</result>