For a manuscript, A needs 6 days to complete the printing, and B needs 10 days to complete the printing, so how much is the manuscript completed by the two of them in 3 days?
一份稿件，甲需要6天才能完成打印，乙需要10天才能完成打印，那么两人合打3天共完成这份稿件的多少．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

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

<gadget id="calculator">(1/6) + (1/10)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">(4/15) * 3</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>