Xiaolan reads a science and technology book. On the first day, she reads 45 pages. On the second day, she reads 1/5 more of the whole book than on the first day, and on the second day, she reads 1/4 of the whole book. How many pages does the book have?
小兰看一本科技书，第一天看了45页，第二天比第一天多看了全书的(1/5)，第二天看了全书的(1/4)，这一本书一共有多少页？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">(1/4) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">45 / (1/20)</gadget>
<output>900</output>

<result>900</result>