To complete a project, A alone needs 8 days, and B completes the project in 2 days (1/5). How many days will it take for teams A and B to work together to complete the project?
完成一项工程，甲单独做需要8天，乙2天完成工程的(1/5)．甲乙两队合作几天完成这项工程？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) / 2</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/8) + (1/10)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">1 / (9/40)</gadget>
<output>40/9 = around 4.444444</output>

<result>40/9 = around 4.444444</result>