Xiao Ming reads a book. On the first day, he reads (1/4) 6 pages more of this book, on the second day he reads (2/5) 2 pages less of this book, and on the third day he finishes reading the rest 17 pages, how many pages does this book have?
小明读一本书，第一天读了这本书的(1/4)多6页，第二天读了这本书的(2/5)少2页，第三天读完剩下的17页，这本书共有多少页？
<gadget id="calculator">17 - 2</gadget>
<output>15</output>

<gadget id="calculator">6 + 15</gadget>
<output>21</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/4) - (2/5)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">21 / (7/20)</gadget>
<output>60</output>

<result>60</result>