A batch of parts can be completed by engineer A in (1/4) hours alone, and engineer B can be completed in (1/6) hours alone, how many hours will it take for engineers A and B to work together on this batch of parts?
一批零件，甲工程师独做要(1/4)小时完成，乙工程师独做要(1/6)小时完成，甲、乙工程师合做这批零件要多少小时．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / (1/4)</gadget>
<output>4</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / (1/6)</gadget>
<output>6</output>

<gadget id="calculator">4 + 6</gadget>
<output>10</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>