It takes 12 days for team A to complete the construction of a canal alone, and 15 days for team B to complete it alone. If the two teams work at the same time, how many days can they complete?
修一段水渠，甲队单独完成要12天完成，乙队单独完成要15天，如果两队同时施工，多少天可以完成？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / (1/6)</gadget>
<output>6</output>

<result>6</result>