Ship a batch of goods, complete alone. Team A needs 10 days, and team B needs 15 days. C team needs 20 days. Now that the three teams are working together, Team A was transferred midway due to work needs. As a result, the other two teams took 6 days to deliver the goods. How many days did Team A actually lose work?
运一批货物，单独完成．甲车队需要10天，乙车队需要15天．丙车队需要20天．现在三队合作，甲车队因为工作需要中途被调走，结果其他两车队共用6天才能将货物运完，甲车队实际少工作了几天？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/15) + (1/20)</gadget>
<output>7/60 = around 0.116667</output>

<gadget id="calculator">(7/60) * 6</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

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

<gadget id="calculator">(3/10) / (1/10)</gadget>
<output>3</output>

<gadget id="calculator">6 - 3</gadget>
<output>3</output>

<result>3</result>