The engineering team needs to lay a 20-meter-long gas pipeline. It has been laying 2 meters every day for 7 days. According to this calculation, how many days will it take to finish laying?
工程队要铺一条长20米的煤气管道，每天铺2米，已铺了7天，照这样计算，还要铺多少天才能铺完？
<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<gadget id="calculator">20 - 14</gadget>
<output>6</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<result>3</result>