One job can be completed by 6 people in 12 days. According to this calculation, if it needs to be completed 4 days ahead of schedule, how many people should be added.
一件工作，6人12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">12 - 4</gadget>
<output>8</output>

<gadget id="calculator">12 / 8</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">6 * (3/2)</gadget>
<output>9</output>

<gadget id="calculator">9 - 6</gadget>
<output>3</output>

<result>3</result>