Using a computer to type a manuscript, it takes 8 hours for A to type alone, and 10 hours for B to type alone. Now, how many hours for A and B to type together to complete this manuscript?
用电脑打一份稿件，甲单独打要8小时，乙单独打要10小时，现在甲、乙合打几小时完成这份稿件？
<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>