To build a road with a length of 6.4 kilometers, the average monthly construction of 1.2 kilometers in the first three months, and the remaining 1.4 kilometers per month, how many months will it take to complete?
筑一条长6.4千米的公路，前3个月平均每月筑1.2千米，剩下的每月修1.4千米，还要几个月完成？
<gadget id="calculator">1.2 * 3</gadget>
<output>3.6</output>

<gadget id="calculator">6.4 - 3.6</gadget>
<output>2.8</output>

<gadget id="calculator">2.8 / 1.4</gadget>
<output>2</output>

<result>2</result>