There is a batch of books that A can bind every day (3/4), and B can bind them in 20 days (5/6). How many days can A and B work together to finish binding?
有一批书，甲每天可以装订(3/4)，乙20天可以装订(5/6)，甲、乙两人合做几天可以装订完？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) / 20</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">(3/4) + (1/24)</gadget>
<output>19/24 = around 0.791667</output>

<gadget id="calculator">1 / (19/24)</gadget>
<output>24/19 = around 1.263158</output>

<result>24/19 = around 1.263158</result>