A project can be completed by team A alone in 12 days and by team B in 10 days alone. In how many days can the two teams work together to complete half of the project?
一项工程，甲队单独做12天可以完成，乙队单独做10天可以完成．两队合做多少天就可以完成这个工程的一半？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/12) + (1/10)</gadget>
<output>11/60 = around 0.183333</output>

<gadget id="calculator">(1/2) / (11/60)</gadget>
<output>30/11 = around 2.727273</output>

<result>30/11 = around 2.727273</result>