To build a road in a certain place, it takes 10 days for engineering team A to complete it alone, and 15 days for engineering team B to complete it alone. If two pairs cooperate, their work efficiency will decrease, and team A can only complete the original (4/ 5), Team B can only complete the original (9/10). Now it is planned to complete the project in 8 days, and the number of days of cooperation between the two teams is required to be as few as possible, so how many days should the two teams cooperate?
某地要修筑一条公路，甲工程队单独干需要10天完成，乙工程队单独干需要15天完成，如果两对合作，他们的工作效率就要降低，甲队只能完成原来的(4/5)，乙队只能完成原来的(9/10)．现在计划8天完成这项工程，且要求两队合作天数尽可能少，那么两队要合作多少天？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 8</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/10) * (4/5)</gadget>
<output>2/25 = around 0.08</output>

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

<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">(1/15) * (9/10)</gadget>
<output>3/50 = around 0.06</output>

<gadget id="calculator">(3/50) - (1/10)</gadget>
<output>-1/25 = around -0.04</output>

<gadget id="calculator">(2/25) + (-1/25)</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">(1/5) / (1/25)</gadget>
<output>5</output>

<result>5</result>