construction team refurbished a 400-meter-long sewer. The project (3/5) was completed in the first 6 days. According to this calculation, how many days will it take for the remaining project to be completed? (Solution with proportional knowledge)
一个工程队整修一段长400米的下水道．前6天完成工程(3/5)，照这样计算，剩下的工程还需几天才能完成？(用比例知识解)
<gadget id="calculator">400 * 6</gadget>
<output>2_400</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">400 * (3/5) * 6</gadget>
<output>1_440</output>

<gadget id="calculator">2_400 - 1_440</gadget>
<output>960</output>

<gadget id="calculator">400 * (3/5)</gadget>
<output>240</output>

<gadget id="calculator">960 / 240</gadget>
<output>4</output>

<result>4</result>