A book, read 15 pages on the first day, read (1/3) of the whole book on the second day, and read 25 pages on the third day just finished the book. How many pages does this book have?
一本书，第一天看了15页，第二天看了全书的(1/3)，第三天再看25页正好看完了这本书．这本书一共有多少页？
<gadget id="calculator">15 + 25</gadget>
<output>40</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">40 / (2/3)</gadget>
<output>60</output>

<result>60</result>