A project was completed in 40 days by team A alone, and 60 days by team B alone. Now the two are working together, and A rests for a few days in the middle. In this way, it takes 27 days to complete the project. How many days did team A rest?
一项工程，甲队独做40天完成，乙队独做60天完成，现在两人合作，中间甲休息了几天，这样共用27天完成，问甲队休息了几天？
<gadget id="calculator">1 / 60</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">(1/60) * 27</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 / 40</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(1/40) * 27</gadget>
<output>27/40 = around 0.675</output>

<gadget id="calculator">(27/40) - 1</gadget>
<output>-13/40 = around -0.325</output>

<gadget id="calculator">(9/20) + (-13/40)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/8) / (1/40)</gadget>
<output>5</output>

<result>5</result>