There are 45 story books in the library, which are literature and art books (5/9), and science and technology books are literature and art books (7/9). How many science and technology books are there?
图书馆有故事书45本，是文艺书的(5/9)，科技书是文艺书的(7/9)，求科技书有几本？
<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">45 / (5/9)</gadget>
<output>81</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">81 * (7/9)</gadget>
<output>63</output>

<result>63</result>