Xiaohong reads a story book. She reads 45 pages in the first week, and (1/4) of the whole book in the second week. She reads 20% less in the second week than in the first week. How many pages does this book have?
小红看一本故事书，第一星期看了45页，第二星期看了全书的(1/4)，第二星期比第一星期少看20%，这本书共有多少页？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/4) / (4/5)</gadget>
<output>5/16 = around 0.3125</output>

<gadget id="calculator">45 / (5/16)</gadget>
<output>144</output>

<result>144</result>