A project, A works in 2 days, B works in 4 days, can be completed (1/2). A works for 4 days, B works for 2 days and can complete (1/3). How many days will the cooperation between A and B be completed?
一项工程，甲工作2天，乙工作4天，可以完成(1/2)．甲工作4天，乙工作2天，可以完成(1/3)．甲乙合作多少天完成．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/2) + (1/3)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) / 6</gadget>
<output>5/36 = around 0.138889</output>

<gadget id="calculator">1 / (5/36)</gadget>
<output>36/5 = around 7.2</output>

<result>36/5 = around 7.2</result>