A project can be completed in 8 days by A alone, and 10 days by B alone, how many days will it take for teams A and B to cooperate to complete it?
一项工程，甲独做8天完成，乙独做10天完成，甲乙两队合作要多少天完成．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 10</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>