It takes Team A 15 days to dig a canal alone, and Team B 12 days to complete it alone. The two teams dug from both ends of the canal at the same time. After 3 days, the distance between the two teams was 660 meters. How long is the canal in meters?
挖一条水渠，甲队单独做要15天完成，乙队单独做要12天完成．两队从水渠两端同时挖，3天后，两队相距660米，这条水渠全长多少米？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/15) + (1/12)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(3/20) * 3</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (9/20)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">660 / (11/20)</gadget>
<output>1_200</output>

<result>1_200</result>