A story book, Xiaoli read (1/3) of this book on the first day, read 20% of it on the second day, and read 63 pages on the third day and just finished it. How many pages does this book have?
一本故事书，小丽第一天看了这本书的(1/3)，第二天看了它的20%，第三天看了63页正好看完，这本书有多少页？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/3) - (1/5)</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">63 / (7/15)</gadget>
<output>135</output>

<result>135</result>