It takes 10 hours to type a manuscript alone, and 8 hours for Xiaogang. If two people work together, how many hours can the manuscript be completed?
打一份文稿，单独打小利要10小时，小刚要8小时，如果两人合打，几小时后可以完成这份文稿？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/10) + (1/8)</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>