A bookshelf is divided into upper and lower layers. (3/4) of the upper shelf is the same as (5/9) of the lower shelf. There are 60 books on the upper shelf, how many books are there on the lower shelf?
一个书架分上、下两层，上层书架的(3/4)与下层书架的(5/9)相同，上层书有60本，下层书有多少本？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">(3/4) / (5/9)</gadget>
<output>27/20 = around 1.35</output>

<gadget id="calculator">60 * (27/20)</gadget>
<output>81</output>

<result>81</result>