Xiao Ming reads a story book. He reads (1/5) of the whole book on the first day, and (3/4) of the whole book on the second day. There are still 25 pages in the book that he has not read. How many pages does this storybook have?
小明读一本故事书，第一天看了全书的(1/5)，第二天看了全书的(3/4)，全书还有25页没有看．这本故事书有多少页？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (1/5) - (3/4)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">25 / (1/20)</gadget>
<output>500</output>

<result>500</result>