The books on the bookshelf include (1/5) popular science books and (1/6) story books. The number of books is between 50 and 70. How many books are there in total on the bookshelf?
书架上的书有(1/5)是科普书，(1/6)是故事书，书的本数在50至70之间，书架上一共有多少本书．
<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<result>60</result>