The engineering team plans to lay a 7.2-kilometer water pipe. In fact, 1.8 kilometers were laid in the first 3 days. According to this calculation, how many days will it take to complete the shop?
工程队计划铺设一条长7.2千米的水管．实际前3天铺设了1.8千米．照这样计算，剩下还要铺几天才能完成？
<gadget id="calculator">7.2 - 1.8</gadget>
<output>5.4</output>

<gadget id="calculator">1.8 / 3</gadget>
<output>0.6</output>

<gadget id="calculator">5.4 / 0.6</gadget>
<output>9</output>

<result>9</result>