Copy a manuscript, A (1/2) hour to finish copying, B (1/3) hour to finish copying, how many hours for the two to copy together.
抄一份稿件，甲(1/2)小时抄完，乙(1/3)小时抄完，两人合抄多少小时抄完．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / (1/2)</gadget>
<output>2</output>

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

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

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

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

<result>1/5 = around 0.2</result>